JPS6218499B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an optical fiber resin coating device.

Optical fiber strands, which are generally formed by spinning glass materials such as quartz, have various characteristics such as low light transmission loss, high flexibility, and light weight.

However, during the manufacturing process of such optical fibers, minute scratches called griffins flow tend to occur on the surface of the optical fibers, and this causes bending of the optical fibers.
In addition to causing deterioration in mechanical strength against tension, etc., after fiber spinning, moisture etc. in the atmosphere is adsorbed over time, which further promotes the growth of flaws, which tends to further deteriorate mechanical strength.

By the way, in order to prevent the occurrence of such scratches, a silicone resin is uniformly coated as a primary coating immediately after spinning the optical fiber, and a thermoplastic resin is further coated as a secondary coating on top of that to give mechanical strength to the optical fiber. Covering with nylon, etc. is practiced.

FIG. 1 shows a sectional view of a main part of a conventional resin coating apparatus for applying a primary coating to an optical fiber.

In the figure, reference numeral 1 denotes a resin coating chamber in a resin coating apparatus, and the resin coating chamber has an inverted conical shape with a nozzle-shaped tip A, and has a capacity of about 100 c.c. This resin coating chamber 1 is filled with approximately 80 c.c. of silicone resin 2, which is a mixture of a predetermined amount of a liquid silicone resin main ingredient and a curing agent for the resin, and an optical fiber strand 3 is filled in the resin coating chamber 1. A primary coating was applied to the periphery of the optical fiber by drying it after passing through it.

However, in the conventional method, after preparing the above-mentioned amount of resin material and once storing it in the resin coating chamber, the optical fiber strand is generally passed continuously for 5 to 6 km through the storage chamber to remove the light. It is common to form a resin coating around the fiber.

Therefore, about 5 to 6 hours have passed between the time when resin coating started and the time when it ended, and the resin material in the storage chamber is gradually hardened by the hardening agent contained in the material. Initially, especially after 5 to 6 hours have passed after mixing the base resin and curing agent, the viscosity becomes extremely high and the resin coating film cannot be uniformly formed around the strands of the optical fiber. The disadvantage of such optical fibers is that their mechanical strength is unstable.

The present invention eliminates the above-mentioned drawbacks, and when coating a long optical fiber with a resin coating material continuously for a long time, the resin coating material in the resin coating chamber is contained in the material. The object of the present invention is to provide a novel resin coating device for optical fibers, which aims to form a uniform resin coating film around an optical fiber strand without being cured by a curing agent.

That is, the present invention provides a means for mixing the base resin and the curing agent by supplying the base resin and the curing agent from a storage chamber that separately accommodates the base resin and the curing agent for an optical fiber coating resin through a base resin supply pipe and a curing agent supply pipe. The main resin and the curing agent are introduced into a resin supply pipe having a resin supply pipe, and the main resin and the curing agent are mixed and continuously supplied to the resin coating chamber within the resin supply pipe.

An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 2 is a schematic diagram of an optical fiber coating apparatus according to the present invention, and FIG. 3 is a sectional view of a main part of a portion M in which the base material and curing agent are mixed in the coating apparatus.

In FIGS. 2 and 3, 11 is a main agent storage chamber that stores a liquid main agent 12 of silicone resin for coating optical fibers, and 13 is a storage chamber that stores a liquid curing agent 14 of the silicone resin. The storage chamber and the discharge ports B and C of the hardening agent storage chamber are respectively connected to a main agent supply pipe 15 and a hardening agent supply pipe 16 formed of thin silicone rubber or the like with a diameter of about 3 mm. 16 is connected to a resin supply pipe 18 inserted into a resin coating chamber 17 for coating silicone resin.

Further, the supply pipes 15 and 16 are provided with rollers 1 as supply amount control means for pressing the supply pipes.
9 and 20 are attached, and by pressing the supply pipes 15 and 16 with these rollers, the amounts of the main resin and curing agent to be supplied are adjusted. Further, a nozzle-shaped glass tube 21 is connected to the tip D of the curing agent supply tube 16 and is arranged so as to open approximately at the center of the resin supply tube 18 .

Further, on the downstream side of the curing agent introduction section consisting of the nozzle pipe 21, as shown in the enlarged view of FIG. 3, there are many pores inscribed in the resin supply pipe 18.
Two mixed thin plates 22 and 23 made of Al or the like are arranged facing each other. In this way, the base agent and the curing agent are passed through the opposing gap of the thin mixing plate and are mixed quietly without introducing air bubbles.

A case will be described in which a long optical fiber is continuously coated with resin using such a resin coating apparatus.

First, the silicone resin coating chamber 17 of the resin coating apparatus shown in FIG. 2 is filled in advance with about 20 ml of silicone resin containing a base resin and a curing agent mixed in a predetermined ratio.

Thereafter, the optical fiber wire 24 is passed through the nozzle portion A of the resin storage chamber 17 at a constant speed to coat the periphery of the optical fiber wire with silicone resin.

At the stage when the optical fiber wire starts to be coated with the resin, the pressing force of the roller 19 of the main agent supply pipe 15 and the roller 20 of the curing agent supply pipe 16 is adjusted so that the main resin and the curing agent are in a predetermined ratio. In this manner, the silicone resin is introduced into the silicone resin supply pipe 18. Here, as shown in FIG. 3, the tip of the curing agent supply pipe 16 has a nozzle shape that opens approximately at the center of the main resin flow path of the resin supply pipe 18, and the hardening agent that is ejected from the nozzle-shaped tip is shaped like a nozzle. The agent passes between two Al mixing thin plates having pores, and is thoroughly mixed with the main agent passing through the resin supply pipe. Then, the silicone resin in which the base resin and the curing agent are sufficiently mixed is supplied to the resin coating chamber 17.

Generally, when a silicone resin is mixed with a base resin and a curing agent, the viscosity increases and hardens in about 5 to 6 hours, but the silicone resin that is initially supplied in a volume of 20ml into the resin storage chamber is placed in the lower part of the resin coating chamber. This amount of silicone resin is consumed within about 2 hours after the optical fiber is coated, and after that, newly formulated resin is continuously supplied, so that the resin coating chamber is The silicone resin always has a constant viscosity,
Therefore, when the optical fiber passes through the resin coating chamber, the resin coating film formed is also uniform. In addition, when mixing the base resin and curing agent, air bubbles are a problem, but the configuration of the mixing section using a perforated thin plate as described above does not have a driving section, so it can be used for a long time. Also, no air bubbles are mixed in.

As described above, by using the optical fiber resin coating device of the present invention, a resin coating film can be uniformly formed around the strands of the optical fiber, and a highly reliable optical fiber with stable mechanical strength can be formed. This gives rise to advantages.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of a conventional optical fiber coating device, FIG. 2 is a sectional view of an optical fiber coating device according to the present invention, and FIG. 3 is a sectional view of a main part of a resin mixing part of a coating device of the present invention. It is. 1: Resin coating chamber, 2: Silicone resin, 11:
Base agent storage chamber, 12: Base agent, 13: Hardening agent storage chamber,
14: Curing agent, 15: Main agent supply pipe, 16: Curing agent supply pipe, 17: Resin coating chamber, 18: Resin supply pipe,
19: roller, 20: roller, 21: glass tube,
22, 23: Mixed thin plate, 24: Optical fiber wire.

Claims (1)

[Claims] 1. A resin coating chamber equipped with a nozzle portion through which the optical fiber to be coated passes, and a storage chamber that separately accommodates a base resin and a curing agent for the resin for coating the optical fiber, and the base resin is supplied to the resin through a base resin supply pipe. A curing agent introduction section is formed by leading the curing agent to the supply pipe and opening the tip of the curing agent supply pipe connected to the curing agent storage chamber approximately at the center of the main resin flow path of the resin supply pipe;
and disposing a mixing thin plate having a plurality of pores inscribed in the resin supply pipe on the downstream side of the curing agent introduction part and facing each other,
An optical fiber coating device characterized in that the base resin and the curing agent are supplied to a resin coating chamber while being mixed between the thin plates.