JPH04131804A - Production of optical fiber - Google Patents

Abstract

PURPOSE:To allow the continuous production of an optical fiber having a uniform outside diameter size and rubber-like elasticity by controlling extrusion speeds in such a manner that the outside diameter of the optical fiber attains a prescribed size and changing the irradiation light quantity of active energy rays, such as UV rays and electron beams, according to this speed. CONSTITUTION:A control section 13 controls pistons 5a, 5b to control the extrusion speeds to extrude a core material 2 and a clad material 3 from double concentrical nozzles 6 in such a manner that the measured value of an outside diameter measuring instrument 7 for measuring the outside diameter of the optical fiber 1 attains the desired outside diameter size. Further, the control section 13 controls a UV irradiating section 8 according to the extrusion speeds to control the quantity of the active energy rays, such as UV rays and electron beams which the optical fiber receives. The optical fiber which is small in the fluctuation in the outside diameter size and has the prescribed outside diameter size is continuously produced in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing an optical fiber, and particularly to a method of manufacturing an optical fiber having rubber-like elasticity and having a constant outer diameter.

[Prior art and problems to be solved] Conventionally, there has been a manufacturing technology for optical fibers having rubber-like elasticity, in which a core material having a three-dimensional mesh structure and having rubber-like elasticity is coated with a crund material having a three-dimensional mesh structure and having rubber-like elasticity. Regarding, JP-A-61
-259202 and Japanese Patent Application Laid-Open No. 64-503, etc., but there is no mention of methods for controlling the dimensions of optical fibers, processing after extrusion (for example, winding), etc.

In general, in the manufacturing process of optical fibers that have rubber-like elasticity, compared to optical fibers made of quartz or plastic, which are hard at room temperature, they are cast by their own weight after extrusion and before the crosslinking reaction, so the outer diameter size can be controlled. is extremely difficult.

In addition, the polymer materials used for the core material and cladding material of optical fibers that have rubber-like elasticity are manufactured at a specific loft, but each loft has completely the same physical properties (extrusion viscosity, etc.). It's not a thing.

Therefore, if the lots of polymeric materials supplied for the core material and cladding material of optical fibers with rubber-like elasticity change, the extrusion viscosity will differ even at the same extrusion pressure, and the diameter of the rubber-like elastic fiber immediately after extrusion will change. As a result, it has been extremely difficult to manufacture optical fibers with rubber-like elasticity and uniform outer diameter dimensions.

The present invention solves the problems of the conventional methods as described above, and allows continuous production of optical fibers having rubber-like elasticity with uniform outer diameter dimensions, while improving the physical properties of the optical fibers. It is an object of the present invention to provide a method for manufacturing optical fibers that does not cause variations.

[Means for solving problems]

In order to achieve the above object, the present invention simultaneously extrudes a core material and a cladding material covering the outer periphery of the core material from a double concentric nozzle with a piston, and crosslinks the core material with an ultraviolet irradiation section. A method for manufacturing an optical fiber in which an optical fiber is wound with a winder using a winder, the control unit controlling the piston so that the measured value of an outer diameter measuring device that measures the outer diameter of the optical fiber becomes a desired outer diameter dimension. control the
The extrusion speed at which the core material and cladding material are extruded from the double concentric nozzle is controlled, and the control section further controls the ultraviolet ray irradiation section according to the extrusion speed so that the optical fiber receives ultraviolet rays, electron beams, etc. This method employs a means to control the active energy dose of the active energy.

[Operation] By employing the above-mentioned means, the present invention controls the extrusion speed via the control unit in accordance with the outer diameter dimension signal of the optical fiber measured by the outer diameter measuring device, and measures the outer diameter of the optical fiber. The diameter dimension is controlled to be a predetermined dimension.

Further, the ultraviolet irradiation section is controlled B to change the amount of irradiation of active energy rays such as ultraviolet rays and electron beams in accordance with the extrusion speed so as to keep the physical properties of the optical fiber constant.

Further, a tension roller acts on the optical fiber wound by the winder to maintain constant tension.

Therefore, the outer diameter of the optical fiber obtained is constant at a desired dimension, and the physical properties of the optical fiber are also constant.

[Example] The present invention will be specifically explained below.

FIG. 1 shows a schematic diagram illustrating a method of manufacturing an optical fiber according to the present invention.

That is, first, the core material 2, which is the raw material for the optical fiber, is put into the sample holder 4a, and loaded into the inner nozzle of the double concentric nozzle 6.

Further, the cladding material 3 is placed in the sample holder 4b and loaded into the outer nozzle of the double concentric nozzle 6.

Next, the core material 2 and cladding material 3 are simultaneously extruded from the double concentric nozzle 6 by pressurization of the pistons 5a and 5b.

Then, the extruded raw optical fiber 1 is passed through an ultraviolet irradiation section 8 equipped with a mercury lamp, and during this passage, the core material 2 and the cladding material 3 are subjected to a crosslinking reaction.

The cross-linked optical fiber 1 has its outer diameter measured by an outer diameter measuring device 7, passes through an auxiliary roller 10 and a tension roller 14, and is exposed to light by the action of a tension controller 11 and a winder 12. The optical fiber 1 is continuously manufactured by winding the fiber 1 under a certain tension.

Here, the outer diameter dimension signal of the optical fiber 1 measured by the outer diameter measuring device 7 is sent to the control section 13 via the signal cable 9, and the extrusion speed of the piston 5a and the piston 5b is controlled by this control section 13. Ru.

Therefore, the molding speed of the optical fiber 1 is controlled and the outer diameter of the optical fiber 1 is kept constant.

In addition, as shown in the crosslinking conditions for the polymer used in the optical fiber 1 shown in FIG.
A CD light amount is required.

When the amount of light irradiated by the ultraviolet irradiation unit 8 is constant,
When the extrusion speed of optical fiber 1 changes, optical fiber 1
may not be able to receive an amount of light commensurate with the crosslinking conditions.

Therefore, in order to obtain an optical fiber 1 with constant physical properties, the amount of irradiation from the mercury lamp of the ultraviolet irradiation section 8 is adjusted to
The control unit 13 performs control according to the extrusion speed.

In this case, as a method for controlling the amount of light irradiated by the mercury lamp of the ultraviolet irradiation section 8 by the control section 13, there is a method of changing the current flowing through the mercury lamp of the ultraviolet irradiation section 8.

That is, the relationship between the current flowing through the mercury lamp of the ultraviolet irradiation section 8 and the amount of irradiated light is as shown in FIG. 3, so that a predetermined amount of irradiated light can be obtained by changing the amount ii passed through the mercury lamp.

Therefore, by changing the flow iii according to the extrusion speed and keeping the amount of light received by the optical fiber 1 before crosslinking constant, it is possible to keep the crosslinking conditions constant and reduce variations in quality.

Note that methods for controlling the amount of light irradiated by the mercury lamp include, in addition to the method of changing the current or voltage applied to the mercury lamp, a method of changing the distance between the mercury lamp and the optical fiber 1, a filter, a filter, etc. There are methods to change the amount of light emitted from the lamp.

It goes without saying that the cross-linking treatment can also be carried out in the same manner by activated fluorophore rays such as ultraviolet rays.

The present invention will be explained in more detail below using experimental examples.

Experimental example-1 The following experiment was conducted using the apparatus shown in FIG.

Core material 2 is a copolymer of ethyl acrylate and dicyclopentynylacrylate (90/10), and 10% of tetraethylene glycol diacrylate is used as a crosslinking agent.
% by weight and 1 weight % of 2-hydroxy-2-methyl-1-phenylpropan-1-one were used.

A copolymer of octafluoropentyl acrylate and dicyclopentyl acrylate (9
0/10) to which 10% by weight of tetraethylene glycol diacrylate and 1% by weight of 2-hydroxy-2-methyl-1-phenylpropan-1-one were added as crosslinking agents was used.

The mercury lamp for ultraviolet irradiation is Ushio's mercury lamp D.
Four EEP-UV lamps (500W) were used.

Further, the initial extrusion pressure of the piston was set at 20 kg1/cj, and extrusion was performed so that the outer diameter of the fiber was within ±0.05 mm.

The above-mentioned core material 2 and crund material 3 were each prepared, and the physical properties of the optical fiber were measured when the amount of ultraviolet light was not adjusted and when it was adjusted.

Table 1 shows the results when the amount of ultraviolet light was not adjusted, and Table 2 shows the results when the amount of ultraviolet light was adjusted.

(Hereinafter, blank space) As is clear from the above results, in the method of adjusting the amount of ultraviolet light according to the present invention, the physical properties of the optical fiber 1 are superior and the quality is constant compared to the method of not adjusting the amount of ultraviolet light. ing.

(Effects of the Invention) By having the above configuration, the present invention can continuously manufacture optical fibers having a predetermined outer diameter with small variations in outer diameter. Since there is no variation in physical properties, it has excellent effects such as no variation in the amount of transmitted light depending on pressure, especially when the optical fiber is used in a pressure-sensitive sensor.

[Brief explanation of the drawing]

Fig. 1 is a schematic explanatory diagram illustrating the method of manufacturing an optical fiber according to the present invention, Fig. 2 is a characteristic diagram showing the relationship between the amount of ultraviolet light and the tensile strength of crosslinked rubber, and Fig. 3 is an ultraviolet lamp in an ultraviolet lamp. FIG. 3 is a characteristic diagram showing the relationship between the current flowing through the sensor and the amount of ultraviolet light. 1... Optical fiber 2... Core material 3... Clad material 4a, 4b... Sample holder 5a, 5b
... Piston 6 ... Double concentric nozzle 7 ... Outer diameter measuring device 8 ... Ultraviolet irradiation section 9 ... Signal cable 10. ... Auxiliary roller 11 ... Tension controller 12 ...
... Winder 13 ... Control section 14 ... Tensing roller 11 Figure 12 Light (mW/cm2)

Claims (1)

[Claims] (1) The core material (2) and the cladding material (3) covering the outer periphery of the core material (2) are simultaneously extruded from the double concentric nozzle (6) by the pistons (5a) and (5b), and A method for manufacturing an optical fiber, in which an optical fiber (1) obtained by crosslinking in an irradiation section (8) is wound in a winder (12), the method comprising measuring the outer diameter of the optical fiber (1). The control unit (13) adjusts the pistons (5a) (5b) so that the measured value of the diameter measuring device (7) becomes the desired outer diameter dimension.
) to control the extrusion speed at which the core material (2) and cladding material (3) are extruded from the double concentric nozzle (6), and further, the control section (13) controls the extrusion speed according to the extrusion speed. A method for manufacturing an optical fiber, characterized in that the ultraviolet irradiation unit (8) is controlled to control the amount of active energy rays such as ultraviolet rays and electron beams that the optical fiber (1) receives.