JPS6344134Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a precoat applicator used in the process of manufacturing a cored optical fiber.

[Conventional technology and its problems]

Conventionally, with precoat applicators that draw out a two-component mixed thermosetting resin while bringing it into contact with a glass fiber, there is a problem that the viscosity of this two-component mixed resin varies widely, and the outer diameter of the resin coating to be applied varies. There is the problem that it is difficult to control the wire drawing speed, etc. in order to maintain a constant outer diameter, and furthermore, scorch tends to occur in the die part of the molding die equipment in a short period of time, and as a result, it is difficult to control the resin coating applied. There were problems such as unevenness (rough skin) on the surface.

[Purpose of invention]

This invention solves these conventional problems, makes it possible to reliably obtain optical fiber core wire with a uniform outer diameter, and enables long-run (long-time) drawing without generating scorch at the die part. The purpose of the present invention is to provide a precoat application device.

[Structure of the idea]

The precoat applicator of the present invention draws out a two-component mixed thermosetting resin while bringing it into contact with a glass fiber to coat the outer surface of the glass fiber with the resin, and once receives the two-component mixed resin. It is equipped with an intermediate receiving pot, a piping system for sending the two-liquid mixed resin from the pot to the molding die device, and a cooling device to cool the molding die device to a predetermined temperature range.

[Explanation of Examples]

Hereinafter, embodiments will be described based on the accompanying drawings.

In FIG. 1, reference numeral 1 denotes a precoat application device, in which a glass preform 3 is fed at a constant speed in the direction of arrow C by a preform supply device 2 and is stretched while being heated and melted in a drawing furnace 4. It is sent to the molding die device 5 of this precoat applicator 1. 6 is the glass fiber drawn in this way,
As shown in FIG. 4, the central portion of the optical fiber core 7 is configured.

This molding die device 5 applies a two-liquid mixed type thermosetting resin to the outer surface of the glass fiber 6, and the applied filament is drawn out from the molding hole 8. A curing furnace 9 is used to immediately heat and dry this.
is provided near the molding hole 8, and the resin of the filament that has passed through the curing furnace 9 is cured and a primary precoat is performed. The resin coating 10 in FIG. 4 is formed in this manner. Note that 11 is a drawing device, which serves to draw the glass fiber 6 mentioned above.

Thus, 12 is a mixing device that can mix two liquids, resin liquid A and resin liquid B, and can control the discharge amount. Reference numeral 13 denotes an intermediate receiving pot with level control that receives the two-liquid mixed resin from the mixing device 12. Reference numeral 14 denotes a piping system that communicates and connects the intermediate receiving pot 13 and the forming die device 5, and in the illustrated example, a pump 15 is interposed therebetween. The two-component mixed resin is pressurized by the pump 15 and supplied to the molding die device 5, and the two-component mixed resin is brought into contact with the glass fiber 6 while being pressurized. 16 is an electric motor whose speed can be controlled like a DC motor, and drives the pump 15 to rotate. 17 is a pressure gauge. Further, the piping system 14 has two parts on the discharge side of the pump 15.
Branched out into books.

Further, the forming die device 5 includes a single die block 17 (not shown) or a split type die block 17, a die 18 having the forming hole 8 and provided at the tip of the die block 17, and a die block 17.
The nipple 19 is inserted into the nipple 19. Then, by the die block 17 and the die 18,
A conical space is formed inside, and the nipple 19
The tip of the nipple 19 is formed in a tapered shape, and the hole at the tip of the nipple 19 and the forming hole 8 of the die 18 are arranged in a straight line, and the outer surface of the nipple 19 and the inner surface of the die block 17, etc. The space 20 formed by the above is filled with a two-liquid mixed resin. That is, two resin inflow passages 21, 21 are formed in the outer diameter direction from the upper end of this space 20, and are opened on the outer surface of the die block 17, and joints 22, 22 are attached to these, and the aforementioned branched passages 21, 21 are formed. Piping 2 of piping system 14
Connect 3 and 23. The resin pressurized by the pump 15 flows into the space 20 via the piping 23 and the resin inflow path 21, is gradually sent to the tip side, and is extruded from the molding hole 8.

24 is a cooling device, and this cooling device 24 cools the inside of the block G surrounded by the imaginary line in FIG. 1 to a predetermined temperature range. That is, the intermediate receiving pot 13 that receives the two-component mixed resin, the piping system 14 including the pump 15 that transports the resin from the pot 13 to the die block 17, and the die block 17 are heated to a predetermined temperature by a cooling device as shown by arrow L. Cool at 24.

Specifically, a cooling hole 25 through which cooling fluid flows is formed in the die block 17, and piping 26, 26 is formed.
The fluid cooled by the cooling device 24 is sent to the die block 17 through the joints 27, 28, etc., and the fluid after cooling the die block 17 is refluxed and circulated, thereby cooling the forming die device 5. are doing.

Of course, although not shown, it is also preferable to provide cooling holes in the die 18 itself or on the nipple 19 side. Reference numeral 28 denotes a temperature detector which sends out a detection signal to control the cooling device 24 and maintain the temperature of the die block 17 and the like at a predetermined low temperature.

Further, as indicated by arrow L in FIG. 1, in order to cool the intermediate receiving pot 13, piping system 14, etc., a pipe through which cooling fluid from the cooling device 24 flows may be inserted into the intermediate receiving pot 13, or It is installed along the container of the intermediate receiving pot 13 and the piping. Alternatively, it is also possible to surround each device or component within the block G with a heat insulating wall, and circulate the inside of the wall for cooling using the cooling device 24.

It is also desirable that the precoat application device 1, cooling device 24, etc. shown in FIG. 1 be attached to the downstream side of the take-off device 11 to perform a secondary precoat (buffer), but these are not shown. Then, by performing primary precoating and secondary precoating (buffering), optical fiber core wire 7 with double coatings 10 and 29 is obtained, as shown in FIG.

As the two-liquid mixture type thermosetting resin, silicone-based, polypyridene fluoride-based, urethane-based, epoxy-based, etc. are used. Naturally, the present invention also includes a case where the pump is omitted from the piping system 14 and the resin is fed to the molding die device without being pressurized (DIP method).

[Effect]

In Figure 2, the horizontal axis shows the elapsed time H after the two-part mixture, and the vertical axis shows the viscosity E of the two-part mixed resin. This shows how things change. From this figure, it can be seen that the viscosity hardly changes at low temperatures, but as the temperature of the resin rises, the viscosity increases rapidly in a short time.

In addition, in Figure 3, the horizontal axis represents the temperature T of the resin, and the vertical axis represents the viscosity E, as in Figure 2.
As a fluid or fluid, it is found that the higher the temperature, the lower the viscosity.

The present invention was made by paying attention to the characteristics of the two-component mixed resin shown in FIGS. Since the temperature is maintained, the viscosity of the resin can be kept almost constant (albeit a little high) at all times, effectively preventing curing of the resin in the molding die device 5, and preventing scorch from occurring in the molding hole of the die 18. , it becomes possible to continue drawing the line for a long time without interrupting it. Furthermore, since scorch does not occur, there is no disturbance in the appearance of the resin coating 10 or 29 (variations in shape and dimensions), and a cored optical fiber with excellent characteristics can be reliably obtained. In addition, since the viscosity E is almost constant, it is possible to control the drawing speed to uniformly draw the outer diameter of the resin coating 10 or 29, or to control the drawing speed of the electric motor 1.
Controlling the discharge amount of the pump 15 (controlling the resin supply amount) by changing the rotation speed of the pump 15 becomes extremely easy.

[Effect of idea]

The present invention was able to effectively achieve the intended purpose with the above-mentioned configuration. In particular, since the viscosity of the two-component mixed resin in the molding die device is maintained constant, variations in the outer diameter of the resin coating due to changes in viscosity do not occur, and high-quality optical fiber core wires can be obtained. It will be done.

Furthermore, since scorch does not occur in the die portion of the molding die device, it has become possible to run the device for a long time. Of course, the appearance of the resin coating will not be disturbed even after long-term use.

Furthermore, when the drawing speed is increased, the appearance of the resin coating is likely to be disturbed unless the curing furnace for heating and drying is provided as close as possible to the die of the forming die device. In this invention, the molding die device including this die is cooled, so even if the curing furnace is brought closest to the molding hole of the die, curing of the resin does not occur and high-quality resin coating can be achieved at high speed. Ta. Moreover, since it has a constant viscosity, it has the advantage of facilitating control of the drawing speed and automatic control of the resin supply amount.

[Brief explanation of drawings]

Fig. 1 is a partial cross-sectional schematic diagram showing an embodiment of the present invention, Fig. 2 is a characteristic diagram showing the relationship between the elapsed time after mixing the two liquids and the viscosity of the resin, and Fig. 3 is the temperature of the resin. FIG. 4 is an enlarged cross-sectional view of the optical fiber core. 5... Molding die device, 6... Glass fiber,
10, 29...resin coating, 13...pot, 14
...Piping system, 15...pump.

Claims (1)

[Claims for Utility Model Registration] 1. In a pre-coat application device that draws out a two-component mixed thermosetting resin in contact with a glass fiber and coats the outer surface of the glass fiber with the resin, the two-component mixed resin is 1. A precoat application device, characterized in that it is equipped with an intermediate receiving pot for receiving the resin, a piping system for sending the two-liquid mixed resin from the pot to a molding die device, and a cooling device for cooling the molding die device to a predetermined temperature range. 2. The precoating application according to claim 1, wherein the piping system for transporting the two-component mixed resin from the pot to the molding die device is equipped with a pump for pressurizing and contacting the two-component mixed resin with the glass fiber. Device.