JPS58100111A - Reinforcing method for optical fiber connection part - Google Patents

Abstract

PURPOSE:To eliminate the need for an injection machine and to reinforce connection easily and speedily by molding by coating at least either one of the circumference of an optical fiber connection part and the recessed part of a mold with an auxiliary agent and then injecting a main agent. CONSTITUTION:At least of either one of the circumference of the connection part 5 of optical fibers 4 and 4 connected by using a resin-coated optical fiber 1 and a mold 2 and the circumferential surface of the recessed part 6 of the mold 2 is coated previously with an auxiliary agent for castable resin 8 to be molded by dissolving it in a solution of alcohol, aceton, etc. The castable resin 8 is set by the contacting with a principal agent and the auxiliary agent and the principal agent is a compound which has a double bond, for example, in a molecule or at a molecule terminal and radical polymerization is induced by the radical generated by peroxide.

Description

[Detailed description of the invention] The present invention relates to a method for reinforcing fiber optic connections.

Generally, the outer periphery of optical fibers for optical communications is coated with a resin such as nylon3. When connecting these resin-coated optical fibers in the longitudinal direction, the resin coating at the ends of the resin-coated optical fibers is removed. Then, the end faces of the optical fibers are butted against each other, and the optical fibers are fused and connected to each other by a heat fusion machine using, for example, a discharge arc. Since the resin coating has been removed from the optical fiber connection portion thus formed, the connection portion is coated with resin again by molding or the like in order to reinforce the mechanical strength.

There is a method of injection molding thermoplastic resin to resin mold the optical fiber connection part, but this method requires an injection machine and is cumbersome to handle, making it unsuitable for on-site work. There is a drawback.

As a method suitable for on-site work, there is a method in which a two-component mixed thermosetting resin composition is injected into a mold and cured. When using this two-component mixed type thermosetting resin composition, the resin composition starts the curing reaction from the moment it is mixed, so the resin composition must be quickly injected into the mold after mixing. Such precautions are required. Furthermore, high temperatures are required to speed up the curing reaction in order to improve workability. However, when the optical fiber splice is heated to high temperatures, the thermal expansion coefficients of the thermosetting resin and the optical fiber are different, so stress is applied to the optical fiber during cooling, resulting in an increase in splice loss. Sometimes.

However, it is not preferable to heat the connecting portion of the optical fiber to a high temperature to harden the resin. In order to keep the splice loss low, heating at a relatively low temperature for a long period of time is sufficient, but this has the disadvantage of worsening workability.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for reinforcing optical fiber connections without the above-mentioned problems.

That is, the method of the present invention is a method of reinforcing the optical fiber connection part by storing the optical fiber connection part in a mold, injecting a casting resin into the mold, and forming a resin coating on the optical fiber connection part. In this method, the casting resin is a resin that hardens when the main resin and the auxiliary agent come into contact with each other, and the auxiliary agent is applied to at least one of the periphery of the optical fiber connection portion and the interior of the mold, and then The method is characterized in that a resin coating is formed on the optical fiber connection portion by injecting the base material into the mold.

EMBODIMENT OF THE INVENTION Hereinafter, one embodiment of the method for reinforcing an optical fiber connection portion of the present invention will be described in detail with reference to the drawings.

In the figure, 1 is a resin-coated optical fiber, and 2 is a mold. The resin-coated optical fibers 1 and 1 have their resin-coated ends removed, and the end faces of the optical fibers 4.4 from which the resin coating 5.5 has been removed are heated using a discharge arc, etc., not shown. Fusion splicing is performed by a fusion splicer. In the figure 5
is the connection part.

The molding die 2 can be divided into upper and lower halves, and a mold cavity is provided in the center of the two halves for molding resin onto the portion of the optical fiber 4.4 from which the resin coating 5.5 has been removed. 6.6 is provided. In this pattern 6, both ends in the longitudinal direction are approximately the same as the outer diameter of the resin coating 5 of the resin-coated optical fiber 1, and the outer diameter of the resin coating 5 is slightly larger in the middle part. There is. In the figure, 7 is a resin injection hole.

Using such a resin-coated optical fiber 1.1 and molding die 2, the method of the present invention can be applied to
The auxiliary agent of the casting resin 8 to be molded is dissolved in a solution of alcohol, acetone, etc., and applied to at least one of the circumferential surfaces of the molding resin 8 in advance by spraying or the like (not shown). The casting resin 8 in the present invention is a resin that hardens when a main agent and an auxiliary agent come into contact with each other. By radical generation of methyl ethyl ketone peroxide (hereinafter referred to as MEK PO), benzoyl peroxide (hereinafter referred to as BPO), tertiary-butyl benzoate, cyclohexanone peroxide, etc. (hereinafter in the present invention, these peroxides are referred to as radical generators). Examples of compounds that induce radical polymerization include the following.

(a) As a urethane compound having a double bond: The end of polypropylene glycol (hereinafter referred to as PPG) polyol with a molecular weight of 100,000 to which ethylene oxide has been added is attached with diphenylmethane diinocyanate (hereinafter referred to as M
(referred to as DI) to which hydroxyethyl methacrylate (hereinafter referred to as HEMA) is added to a prepolymerized product; (b) as a diallyl phthalate compound having a double bond; (c) an unsaturated polyester compound having a double bond; In this example, the auxiliary agent is a compound that causes radical decomposition in a radical generator such as MEKPO or BPO by an ionic reaction (this reaction is hereinafter referred to as a redox reaction, and this compound is hereinafter referred to as a radical promoter). For example, cobalt naphthenate.

Furthermore, the area around the connecting portion 5 of the optical fiber back 4 in the present invention includes the connecting portion 5 of the optical fiber 4.4, the portion of the optical fiber 4.40 from which the coating 5 has been removed, and a portion of the terminal of the coating 5. .

After applying an auxiliary agent to at least one of the periphery of the optical fiber 4, the rare connection part 5, and the circumferential surface of the mold recess 6, the optical fiber 4,
The connecting portion 5 is set in the depression 6 of the molding die 2, and the base resin is injected through the resin injection hole 7 as shown in FIG. Since the radical generating agent is mixed in advance in this main material, the auxiliary agent, ie, the radical promoter applied to at least one of the periphery of the connection part 5 and the circumferential surface of the mold 6, and the radical generating agent in the main material are mixed together. come into contact and cause a redox reaction. When the radical generator causes radical decomposition by a redox reaction, the base material starts to have a radical weight of 1 weight and rapidly hardens to achieve temperatures of -7.F, molding, and 1.

In the above embodiment, a radical accelerator was applied as an auxiliary agent to at least one of the optical fiber 4, the periphery of the rare connection part 5, and the mold groove 6. The radical generator is applied to the connection part of the optical fiber 4.4.In this case, it is necessary to mix the radical promoter into the main agent in advance. The radical accelerator mixed in the main material is injected into the mold together with the main material 1, and the auxiliary agent, i.e., the radical generator, is pre-applied around the connection part 50 and at least one of the mold 6. contact with the radical generator to cause radical decomposition. As a result, the main ingredient, ie, the radically polymerizable compound, starts radical polymerization and becomes a polymer, thereby achieving the desired resin molding on the optical fiber connection portion.

Example 1゜Optical fiber diameter 125 μmφ, nylon coating outer diameter 0.9-
Outer diameter 1.2 + mφ length 4 for each of the 10 connections of the optical solver 1 with the removal length of the φ connection part 20111111
Mold molding was carried out as follows over a period of 0.0 cm.

An alcohol aqueous solution with a concentration of 5% cobalt naphthenate was applied by spray to the area around the optical fiber connection, and the optical fiber connection was placed in a mold.

Then, a urethane methacrylate mixture, which is a reaction product of HEM'A and a prepolymerized PPG polyol containing 1% butyl bendoate, was injected through the injection hole of the mold. After 5 minutes, the mold was removed and a resin was molded onto the optical fiber connection part.

The resulting resin on the optical fiber connection was completely cured in all cases and had good flexibility.In addition, the resin was molded onto the optical fiber connection. There was no change in connection loss compared to the connection before molding.

Example 2 Ten optical fiber connection parts similar to those in Example 1 each having an outer diameter of 1.2mm and a length of 110w+1 were molded as follows.

: Spray an acetone solution containing 5% concentration of dichlorohexanone peroxide into the cavity of the mold, then set it in the mold for the connection part of the optical fiber, and add 0.8% naphthenic acid solution. A mixture of urethane and tuffrylate containing HEMA was injected into the injection hole of the mold, and the mold was removed after 5 minutes.

The resin on the optical fiber connection portion thus obtained was completely cured and had good flexibility in all cases. In addition, there was no change in connection loss in the optical fiber connection portion molded with resin compared to the connection portion before resin molding.

In the above examples, a compound that undergoes radical polymerization was used as the main ingredient, but a two-liquid contact curing compound that undergoes a polymerization reaction by cyanurate formation may also be used as the main ingredient.

This compound is, for example, a previlimer prepared by adding 2 moles of ethylene oxide to 17 polypropylene glycol and reacting it with 2 moles of diisocyanate, and having an incyanate content of 2 to 50 times (hereinafter referred to as this example). In some cases, this compound (referred to as incyanate-containing prepolymer) can be used as the base material. This compound has the following formula.

Potassium octylate can be used as an auxiliary agent for the main ingredient which undergoes the polymerization reaction by cyanuration.

Example: Using a polypropylene glycol-ethylene oxide-isocyanate compound containing 10% isocyanate as the main ingredient and an acetone solution containing 25% potassium octyl yeast as an auxiliary agent, an optical fiber connection similar to that in Example 1 was made. Mold molding was performed as follows over diameter 1.2 wnφ length ljO+s (number of experiments 1δ times)
.

The auxiliary agent was applied by spray around the optical fiber connection part and the mold hole of the mold, the connection part of the optical fiber was set in the mold, and the main material was injected through the injection hole of the mold. In either case, when the mold was removed after 5 minutes, the resin on the optical fiber connection part was completely cured, and a molded connection part was obtained. In all cases, the molded optical fiber connection portion showed almost no change in connection loss compared to before molding.

In the above embodiment, the mold used is a mold that can be divided into two, but in the present invention, the mold is a sleeve-shaped mold that is not divided into two as shown in FIG. shall also be included. When using a sleeve-shaped mold as shown in FIG. 5, molding is performed as follows to reinforce the connection portion.

First, before the optical fiber 4.4 is connected, the sleeve 9 is inserted into one of the coated optical fibers 1, and then the end faces of the optical fibers 1.1 are fusion spliced to each other, and the connected portion of the optical fiber is connected. An auxiliary agent is applied around the periphery, the sleeve 9 is moved to cover the optical fiber connection part, and the main agent is injected from the resin injection hole 10 of the sleeve 9. Note that, after the resin 11 has hardened, the sleeve 9 can be used as it is as a reinforcing member for the connecting portion without being removed from the connecting portion.

As explained above, the method for reinforcing the optical fiber connection part of the present invention is to apply an auxiliary agent to at least one of the periphery of the optical fiber connection part and the depression of the mold, and then inject the main agent. Therefore, it does not require a machine such as an injection molding machine, and unlike thermosetting resins that harden by thorough mixing, there is no need to apply heat to quickly harden them, so there is no stress on the joints. The connection can be easily and quickly molded and reinforced without affecting the connection loss.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a fiber and a mold used in one embodiment of the present invention, Fig. 2 is a partially omitted sectional view of the same embodiment, and Fig. 3 is a partially omitted sectional view showing another embodiment. It is a diagram.

Claims (3)

[Claims] (1) A method for reinforcing an optical fiber connection by covering the optical fiber connection with a mold and injecting a casting resin into the mold to form a resin coating on the optical fiber connection, The casting resin is a resin that hardens when the main resin and the auxiliary agent come into contact with each other. 1. A method for reinforcing an optical fiber joint, comprising injecting a base agent into the fiber to form a resin coating on the optical fiber joint. (2) A method for reinforcing an optical fiber connection portion according to claim 1, characterized in that a compound that undergoes radical polymerization is used as the main agent, and a compound that causes a radical reaction in the main agent is used as an auxiliary agent. (3) Reinforcing force θ, 1,