JPS598774Y2 - Optical fiber coating material coating equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coating device used for coating an optical fiber with a coating material.

Optical glass fibers are easily scratched on the surface, and the occurrence of scratches greatly reduces their practical strength.

In order to avoid this, attempts have been made to form a protective film by coating and drying a coating material on the surface of the optical fiber immediately after spinning the optical fiber.

It is known that the strength of an optical fiber coated in this manner is greater than an order of magnitude greater than that of an uncoated optical fiber.

In order to obtain a uniform coating, it is necessary for the coating equipment used in the coating process to accurately shape the fiber passage hole, and in order to achieve the purpose of coating, it is necessary to precisely shape the fiber passage hole during coating. must avoid injury.

Conventionally, coating devices have generally been made of metal, plastic, or rubber, but metal has good mechanical precision and can form passing holes with high precision, but it is easy to damage the fiber, and plastic rubber Although it does not damage the fiber, it has the disadvantage that the mechanical precision is poor, the desired fiber passage hole cannot be obtained, and a uniform coating cannot be obtained.

In order to eliminate these drawbacks, the present invention forms a thin polymer film on the inner surface of a die with good mechanical precision, which does not damage the fiber.

The present invention will be explained in detail below with reference to the drawings.

Figure 1 shows the structure of the drawing device used in the present invention, where 1 is an optical fiber preform, 2 is a preform feed, 3 is a heating furnace, and 4 is a wire drawing device.
6 is a fiber, 6 is a drying oven, 7 is a capstan or a drum, and 5 is a coating device of the present invention, an enlarged view of which is shown in FIG. 2, which will be described later.

To operate the drawing apparatus shown in FIG. 1, a fiber preform 1 is attached to a preform feed 2 and gradually inserted into a heating furnace 3.

The fiber preform 1 is heated and softened in a heating furnace 3 and drawn into a fiber 4.

After the fiber 4 has been drawn, it is immediately coated with plastic by a coating device 5 and dried in a drying oven 6 to form a plastic coating.

FIG. 2 shows an embodiment of the present invention, in which 8 is a die base material, 9 is a die base material, and 9 is a die base material;
is a polymer thin film.

The die base material of the coating device in this invention is brass,
Examples of metals such as aluminum and copper include, but are not limited to, chlorocarbon polymers such as poly p-xylylene, polyimide epoxy resin, silicone resin, or Teflon as polymer materials forming the polymer thin film. can give.

In the present invention, casting,
Methods such as vapor deposition, plasma polymerization, electrodeposition, spray, electrostatic coating, dipping, roller coater, and fluidized dipping can be applied, but vapor deposition, plasma polymerization, and spray methods are suitable for forming a uniform thin film. .

In addition, the optical fiber in the present invention is usually made of silica glass having a waveguide structure or silica glass containing an alkali metal or a super-alkali metal, and has a diameter of 100 mm.
~200μm monofilament.

Examples will be described below.

Example 1 A thin film of 30OA poly p-xylylene was formed on the inner surface of the die using a vapor deposition method. Polyurethane was applied to the quartz optical fiber immediately after being drawn using a brass coating device, and the film was dried and hardened in the next step. Ta.

The resulting optical fiber coating was uniform, with an average strength of 540 kg/mm2 and a minimum strength of 480 kg/m2.
Atta in m2.

Example 2 Using an aluminum coating device that formed a 2 μm thin film of epoxy resin on the inner surface of the die by spraying,
Applying polyurethane to the quartz optical fiber immediately after drawing,
In the next step, it was dried and cured.

The resulting optical fiber coating was uniform, with an average strength of 538 kg/mm2 and a minimum strength of 492 kg.
/mm2teatta.

Example 3 Polyurethane was applied to the quartz optical fiber immediately after spinning using a brass coating device that formed a 2 μm thin film of hexamethyldisiloxane on the inner surface of the die by plasma polymerization, and then the following steps were carried out. It was dried and cured in the process.

The resulting optical fiber coating was uniform, with an average strength of 522 kg/mm and a minimum strength of 490 kg/mm.
It was 2.

Example 4 In Example 3, norbornadiene was used instead of hexamethyldisiloxane, and the average strength was 527 kg/mm.
2. An optical fiber with a minimum strength of 488 kg/mm2 was obtained.

Comparative Example 1 After applying polyurethane using a brass applicator,
In the next step, it was dried and cured.

The average strength of the obtained optical fiber was 502 kg/mm2,
The minimum strength is 180 kg/mm2.

Comparative Example 2 Using a coating device made of silicone resin, polyurethane was coated on an optical fiber immediately after spinning, and then heated and cured.

The average strength of the obtained optical fiber was 538 kg/mm2, but the coating surface was non-uniform.

As explained above, the optical fiber coating material application device of the present invention has a thin polymer film on the inner surface of the die made of metal with good mechanical precision, so that a uniform coating can be obtained and the optical fiber will not be damaged. Since there is no fiber, there is an advantage that a high-strength fiber can be obtained.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the structure of an optical fiber drawing apparatus, and FIG. 2 is a diagram showing an embodiment of the present invention. 1... Base material for fiber, 2... Base material feeding, 3... Heating furnace, 4... Fiber,
5...Coating device, 6...Drying oven, 7.
...Capstan or drum, 8...
Dice base material, 9... Polymer thin film.

Claims (1)

[Scope of utility model registration request] An apparatus for applying plastic to the surface of an optical fiber using a die, characterized in that the die is formed of metal having a thin polymer film on its inner surface.