JP2016204240A - Method for manufacturing optical fiber strand or optical fiber core wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical fiber strand or optical fiber core wire manufacturing method which can efficiently cure an ultraviolet curable coating material, applied to an outer periphery of a quartz fiber or an optical fiber strand, using an LED.SOLUTION: In an optical fiber strand or optical fiber core wire manufacturing method which applies an ultraviolet curable coating material to an outer periphery of a quartz fiber or an optical fiber strand and irradiates ultraviolet rays to cure the coating material, the ultraviolet irradiation is performed using a plurality of LEDs having different emission wavelengths.SELECTED DRAWING: None

Description

  The present invention relates to a method for manufacturing an optical fiber or an optical fiber.

2. Description of the Related Art Conventionally, an optical fiber has been applied to a high-power metal halide lamp, high-pressure mercury lamp, or other HID lamp (high-pressure mercury lamp) while applying an ultraviolet curable coating material (Patent Documents 1 to 3) to the outer periphery of a quartz fiber that is drawn at high speed. It was manufactured by irradiating ultraviolet rays from an intensity discharge lamp) to advance the curing reaction of the coating material.
In recent years, ultraviolet light emitting diodes (ultraviolet LEDs; hereinafter simply referred to as “LEDs”) having a light emission wavelength in the ultraviolet region and capable of generating strong ultraviolet rays have been developed. Studies are underway to produce optical fiber strands or optical fiber core wires (hereinafter also collectively referred to as “optical fibers”) using LEDs having a long life as a light source (Patent Documents). 4).

HID lamps used in the production of optical fibers have a continuous spectrum and include from short wavelengths to long wavelengths, so they also match the absorption wavelength region of photopolymerization initiators and act efficiently on the initiators. The coating material was easy to cure.
On the other hand, since the LED has an emission spectrum composed of a narrow wavelength region, the curing behavior of the ultraviolet curable coating material differs depending on which wavelength the LED has an emission wavelength. In general, LEDs using an emission wavelength centered at 365 to 405 nm are being put into practical use for optical fiber manufacturing applications. However, the emission wavelength of the LED and the absorption wavelength region of the photopolymerization initiator are not easily matched. Infrared radiation from is less than in the case of HID lamps, so it was difficult to cure the coating material efficiently.

JP-A-5-306146 JP-A-5-306147 JP 2001-130929 A JP 2003-089555 A

  The present invention relates to a method of manufacturing an optical fiber or an optical fiber that can efficiently cure an ultraviolet curable coating material applied to the outer periphery of a quartz fiber or an optical fiber using an LED. The purpose is to provide.

  The present inventors have found that if UV irradiation is performed using a plurality of LEDs having different wavelengths, the present invention has been completed by effectively acting on the photopolymerization initiator and sufficiently curing the coating material. .

That is, the present invention relates to a method of manufacturing an optical fiber or an optical fiber core, in which an ultraviolet curable coating material is applied to the outer periphery of a quartz fiber or an optical fiber, and the coating material is cured by irradiating ultraviolet rays. The present invention provides a method of manufacturing an optical fiber or an optical fiber, wherein the ultraviolet irradiation is performed using a plurality of LEDs having different emission wavelengths.
In this specification, the “emission wavelength” of an LED is a wavelength that forms the peak of the maximum emission intensity in the emission spectrum showing the wavelength dependence of the emission intensity of the LED. The wavelength that gives the maximum value of the peak. In the technical field of the present invention, the emission wavelength of an LED is generally referred to as a central emission wavelength, a main emission wavelength, a peak wavelength, or the like.

  According to the present invention, an ultraviolet curable coating material applied to the outer periphery of a quartz fiber or an optical fiber can be efficiently and sufficiently cured by using an LED while reducing the influence of curing inhibition by oxygen gas. Thus, the optical fiber or the optical fiber can be efficiently manufactured.

In the present invention, the optical fiber means a layer having a multilayer coating structure in which a flexible primary coating layer is provided in contact with the surface of the quartz fiber and a highly rigid secondary coating layer is provided on the outside thereof.
In addition to the optical fiber strand, the optical fiber core wire is an optical fiber pigmented wire provided with a colored layer on the outside of the optical fiber strand, and a plurality of optical fiber pigmented wires are bundled into a tape shape with a tape layer. Optical fiber tape.

The UV curable coating material may be any general UV curable optical fiber coating material usually used for coating optical fibers, and contains a normal photopolymerization initiator.
Examples of the photopolymerization initiator include 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, xanthone, fluorenone, benzaldehyde, fluorene, anthraquinone, triphenylamine, carbazole, 3-methylacetophenone, 4- Chlorobenzophenone, 4,4'-dimethoxybenzophenone, 4,4'-diaminobenzophenone, Michler's ketone, benzoin propyl ether, benzoin ethyl ether, benzyl dimethyl ketal, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropane -1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, thioxanthone, diethylthioxanthone, 2-isopropylthioxanthone, 2-chloro Thioxanthone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis- (2,6-dimethoxybenzoyl)- 2,4,4-trimethylpentylphosphine oxide, 1,2-octanedione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)], ethanone, 1- [9-ethyl-6- (2 -Methylbenzoyl) -9H-carbazol-3-yl]-, 1- (O-acetyloxime) and the like. Examples of these commercially available products include Irgacure 184, 369, 651, 500, 907, 819, 1700, 1850, OXE01, OXE02, DAROCURE1173, LUCIRIN TPO (manufactured by BASF), Ubekrill P36 (manufactured by UCB), and the like.
The photopolymerization initiator may be used alone or in combination of two or more.

In the present invention, the ultraviolet curable coating material as described above is applied to the outer periphery of a quartz fiber or an optical fiber, and is cured by irradiating ultraviolet rays.
A plurality of LEDs having different wavelengths are used for ultraviolet irradiation. These wavelengths are not particularly limited as long as they are wavelengths in a region generally classified as ultraviolet rays, but LEDs having an emission wavelength in a wavelength region of 250 to 350 nm (deep ultraviolet wavelength) and 365 to 405 nm (this specification) For convenience, it is preferable to irradiate ultraviolet rays by combining LEDs having emission wavelengths in the wavelength region of “normal ultraviolet wavelength” for convenience.
In a mode in which deep ultraviolet rays and normal ultraviolet rays are combined and irradiated with ultraviolet rays, both may be irradiated simultaneously or sequentially. When sequentially irradiating, it is preferable to irradiate deep ultraviolet rays first.

  Since the photopolymerization initiator generally has higher absorption efficiency of short-wavelength ultraviolet light than long-wavelength ultraviolet light and high absorption efficiency of deep ultraviolet wavelength, deep ultraviolet light is mainly absorbed near the surface of the coating layer. As a result, even in an optical fiber manufacturing process that draws at a high speed, a coating layer with a high surface curability can be obtained because the curing reaction proceeds more rapidly on the surface of the coating layer than when only ordinary ultraviolet rays are used. Can do. On the other hand, normal ultraviolet rays are mainly absorbed inside the coating layer. As a result, a coating layer in which the curing reaction has sufficiently progressed to the inside of the coating layer can be obtained as compared with the case where only deep ultraviolet rays are used.

For the ultraviolet irradiation, an ultraviolet irradiation device including a plurality of LEDs having different emission wavelengths can be used, and the arrangement of the plurality of LEDs is not particularly limited, either in parallel or in series with respect to the drawing direction of the optical fiber. good. In addition, a plurality of LEDs having different emission wavelengths may be arranged in one light source unit, and light source units having a plurality of LEDs having different emission wavelengths for each light source unit may be connected in series.
For ultraviolet irradiation, an ultraviolet irradiation device including an LED having an emission wavelength in a wavelength region of 250 to 350 nm (deep ultraviolet wavelength) and an LED having an emission wavelength in a wavelength region of 365 to 405 nm (normal ultraviolet wavelength) is used. Is preferred. The arrangement of the LED having the emission wavelength in the deep ultraviolet wavelength region and the LED having the emission wavelength in the normal ultraviolet wavelength region is not particularly limited, and may be either in parallel or in series. Further, in one light source unit, an LED having a light emission wavelength in a deep ultraviolet wavelength region and an LED having a light emission wavelength in a normal ultraviolet wavelength region may be arranged together. A single LED light source unit having an emission wavelength in any region of the ultraviolet wavelength, and a plurality of units having different emission wavelengths may be connected in series.

  Ultraviolet irradiation by LED can be performed by a normal method, and irradiation output, irradiation time, and the like can be selected as appropriate.

  EXAMPLES Next, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these Examples at all.

Example 1 and Comparative Example 1
An optical fiber was manufactured at a drawing speed of 200 m / min using a drawing device manufactured by Yoshida Kogyo. The quartz base material used was Suprasil-F300 manufactured by Shin-Etsu Quartz. The covering material used was JSR R1175 as the primary coating and JSR R3038M as the secondary coating. A quartz base material is melt-spun to a diameter of 125 μm, two coating materials are simultaneously coated thereon, and the coating material is cured by irradiating ultraviolet rays with an LED light source unit, which will be described later, to form an optical fiber strand having a diameter of 250 μm. Obtained. The nitrogen gas purge of the LED light source unit was performed at a flow rate of 10 liters / minute.
About about 100 obtained optical fiber strands were bundled and shaken, and the sticking condition (bundling feeling) of optical fiber strands was evaluated. The worse the surface cured state, the worse the bundle feeling (easily sticking the optical fiber strands), which is not preferable. The results are shown in Table 1.
Example 1
As the LED light source unit, one light source unit having an emission wavelength of 280 nm and an input power of 1 kW and one light source unit having a wavelength of 365 nm and an input power of 1 kW were used side by side.
(Comparative Example 1)
Two LED light source units with an emission wavelength of 365 nm and an input power of 1 kW were used side by side.

From the results in Table 1, it is shown that the method of curing the coating material by irradiating ultraviolet rays using a plurality of LEDs having different emission wavelengths has better bundled feeling of optical fiber strands and better surface curability. The results shown are obtained.
As described above, ultraviolet irradiation is performed using a plurality of LEDs having different emission wavelengths, so that an ultraviolet curable coating material applied to the outer periphery of a quartz fiber or an optical fiber can be efficiently and sufficiently applied using an LED. It can be hardened and an optical fiber strand or an optical fiber core wire can be manufactured efficiently.

Claims (3)

  In the manufacturing method of an optical fiber strand or an optical fiber core wire, an ultraviolet curable coating material is applied to the outer periphery of a quartz fiber or an optical fiber strand, and the coating material is cured by irradiating ultraviolet rays. A method of manufacturing an optical fiber or an optical fiber, characterized by using a plurality of LEDs having different wavelengths.   The manufacturing method according to claim 1, wherein an LED having an emission wavelength in a wavelength region of 250 to 350 nm and an LED having an emission wavelength in a wavelength region of 365 to 405 nm are combined and irradiated with ultraviolet rays.   The manufacturing method of Claim 1 or 2 using the ultraviolet irradiation device provided with LED which has a light emission wavelength in the wavelength range of 250-350 nm, and LED which has a light emission wavelength in a 365-405 nm wavelength range.