JPS5869735A - Coating method of optical fiber - Google Patents

Abstract

PURPOSE:To obtain an optical fiber having a uniform coating and improved adhesiveness to the fiber, by passing the optical fiber through a thermoplastic resin pipe, and hot-drawing the pipe while rotating the pipe. CONSTITUTION:A base material 1 is slowly inserted in a fiber drawing furnace 3 by a base material feeding apparatus 2, and heated in the fiber drawing furnace 3 and spun into an optical fiber 5. The outside diameter of the optical fiber 5 is then read by an outside diameter measuring apparatus 4, and the optical fiber 5 is passed through a pipe 6 consisting of a thermoplastic resin. The pipe 6 is rotated by a rotating belt 7 or rotating arm 13 while inserted slowly in a heater 9 by a pipe feeding apparatus 8. The pipe 6 is locally heated by the heater 9, and the thermoplastic resin is applied to the optical fiber 5. The coated outside diameter of the resultant coated optical fiber 10 is read by an outside diameter measuring apparatus 11, and the optical fiber 10 is then wound by a winder 12.

Description

[Detailed description of the invention] This invention relates to a method of coating with a pipe made of flexible resin.

In order to maintain the initial strength of the original fiber, in the past, a liquid resin composition was generally applied to the original fiber after spinning, and in the next process, a liquid resin composition was applied to the original fiber immediately after spinning. A method of solidifying by heating, irradiation, or cooling has also been adopted.

However, since this method uses a liquid resin composition, it is difficult to form a uniform coating on the outer periphery of the fiber.
It was located away from the center of the membrane. This drawback-
In order to solve the problem, the inventors of the present invention
ruJ, (Unexamined Japanese Patent Publication No. 1973-//7λOda)'
As shown in 1977-1077, a thermoplastic resin pipe is heated and softened to form a base fiber.
We proposed a method to resolve the issue.

However, since there is generally some non-uniformity in the wall thickness of plastic pipes in the pincer direction and radial direction, there is a drawback that when this plastic pipe is coated on the Hikari 7 Eyer, non-uniformity occurs in the device film thickness. In addition, there is some non-uniformity in the direction of the spinning force in the optical fiber base material, and in order to always obtain a constant fiber outer diameter, this is controlled by changing the spinning process, but in this case, the heating of the pipe If the conditions are not strictly specified [#L, 4! between the spun fiber and the d film! I! The defect of poor y-layer properties was rare.

In order to solve these drawbacks, the present invention rotates the covered plastic pipe, and the present invention will be described in detail below with reference to the FA side.

Book opening'? i: To print, enter 7 in Figure 1 or Figure 2.
J<1. A reliable outfit d is used. To operate this, the base material 1 is constantly inserted into the furnace 3 by the wire 51 by the base material feed λ. The base material l is heated to IJu in the drawing furnace 3,
The original fiber j is spun. The spun optical fiber is passed through a vibrotube consisting of 6 rows of hardness and heat resistance, whose outer diameter is read by an outer diameter-reverse test. Is the vibro gradually heated by pipe feeding? While being inserted into the interior, it is rotated by the rotating belt 7 or rotating arm 13. The vibro is locally heated by the heater 9, and the thermoplastic #dl is broken into optical fibers. After the temporary outer diameter of the coated optical fiber /θ is read by the film thickness l1111/l, it is wound 8 times by the winder Ill&/2.

The rotational speed of the pipe in the present invention is not limited to a certain point, but the higher the rotational speed, the better the uniformity of the f&- film thickness and the density of the fiber and coating, but on the other hand, the higher the rotational speed, the higher the
Since the rotation may give vibration to the spinning device 2, it is determined by the force/negotiation between the master Mr. Q and the spinning speed. Embodiment F will be described below.

Example 1 An optical fiber base material with an outer diameter of 2tIIJI was heated and softened to form an aO
trrA+ was spun once into an optical fiber with an outer diameter of 1 μm.

The optical fiber is passed through a polypropylene pipe with an outer diameter of 〃■ and an inner diameter of 10IIIIII, and the pipe is
It was inserted into the heater at a speed of about 1/2/min while rotating at 1/2 pm. The pipe was JJO heated to about 200° C. to coat the optical fiber with a thermal gTm resin. After the film thickness of the optical 7 eyer was read by a film thickness III device, the optical 7 eyer thus installed was wound up.
- It was extremely uniform with a diameter of 10±7 μm, and the fiber and coating were well layered.

Example 2 An optical fiber base material with an outer diameter of 2 s was softened by heating and spun into an optical fiber with an outer diameter of 1λSμ at a speed of 30 spindles/min.

The original fiber was passed through a polyethylene pipe having an outer diameter of approximately 70 cm and an inner diameter of 70 cm, and the pipe was inserted into the reactor at a speed of approximately 15 mm while the pipe was rotated at a speed of 15 rpm. The pipe was heated to about 30° C. to coat the optical fiber with hot gT loosely injected resin. After the film thickness was read by a film thickness reversal device, the optical fiber was wound up.

The thickness of the obtained optical fiber is 7 inches long
〃±lμ votes over m, with excellent uniformity of 17
a. In addition, the coating was well densely layered on the fiber. Comparative Example 1 In Example 1, without rotating the pipe, the thermoplastic qd
m was deposited on the original fiber. II of the obtained fiber
The I thickness is lo ± 2.0 mm per fiber length l. It was a joke.

As explained above, according to the optical fiber coating method of the present invention, the thermoplastic resin DM is fsi-formed into the original 7-eyeper while rotating the pipe, so that it has a uniform film thickness and is bonded to the fiber. There is an advantage that an optical fiber having a dense V1 temporary film can be obtained.

[Brief explanation of the drawing]

FIGS. 1 and 2 are configuration diagrams of the apparatus used in the present invention. /...Base metal, λ...Base material feed, 3...Drawing furnace, Tei...Outer diameter 111Il constant u, s...Optical fiber, ≦・
... Pipe, 7... Rotating belt, l... Pipe feed, ? ... heater, 10 ... coated original fiber,
ll... Film thickness l1li machine, /2... Winding machine, /3.
・Rotating arm. Patent applicant: Nippon Telegraph and Telephone Public Corporation 4() 2 U? 1

Claims (1)

[Claims] L In the method according to the original 7 Aiper, the raw fiber immediately after spinning is passed through a pipe made of thermoplastic resin, the pipe is heated and abraded, and the thermoplastic resin is broken into the raw fiber. A method for producing original fibers, which is characterized by rotating the pipe.