JPH11302039A - Production of colored optical fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the adhesion property to the secondary layer of an optical fiber and the adhesion property to an integral coating resin when a coated optical fiber is formed by coating the optical fiber with an uncured UV curing resin contg. coloring pigments and curing the resin in such a manner that a specific curing degree is attained. SOLUTION: The optical fiber 2 previously provided with a primary layer and secondary layer is delivered from a delivery bobbin 1 and is passed through a coloring ink coating device 3 by which the coloring ink is applied thereon. The fiber is then passed through a coloring ink curing device 4 having a UV irradiation lamp, whereby, the UV curing resin is cured and the colored optical fiber 5 is formed. The colored optical fiber is taken up on a take-up bobbin 6. The desired colored layer is obtd. by regulating the output of the UV irradiation lamp of the coloring ink curing device 4 in such a manner that the curing degree of the resin attains 80 to 90%. The colored optical fiber 5 is made into optical fibers which are then made into a coated fiber ribbon by the integral coating resin but there is no partial peeling and the peeling of the colored layers at the time of separating the coated fiber to the individual fibers is obviated as well.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a colored optical fiber having a colored layer as the outermost layer of the optical fiber.

[0002]

2. Description of the Related Art An optical fiber strand obtained by melt-spinning an optical fiber preform is usually provided with a primary layer and a secondary layer sequentially for protection thereof, and further, on its outer peripheral surface,
A coloring layer for identification is formed. Incidentally, the primary layer and the secondary layer are cured films of an ultraviolet curable resin,
The coloring layer is a cured film of a coloring ink obtained by blending a coloring pigment with an uncured ultraviolet curing resin. FIG. 1 schematically shows a production process of the colored optical fiber, and a delivery bobbin 1 is shown.
From the optical fiber 2 provided with a primary layer and a secondary layer in advance,
To apply a colored ink, and then through a colored ink curing device 4 having an ultraviolet irradiation lamp to cure the ultraviolet curable resin of the colored ink to form a colored optical fiber 5, which is wound on a winding bobbin 6. It is manufactured continuously by winding.

By the way, this colored optical fiber 5 is
In general, a plurality of the fibers are collectively coated in a state of being arranged in a plane to form a single optical fiber tape core, which is generally formed into a cable. This optical fiber ribbon is separated into individual optical fiber strands by peeling the resin for collective coating in order to connect various devices and tape ribbons during installation. In some cases, the colored layer may also be peeled off and become indistinguishable. Therefore, in order to prevent the peeling of the colored layer, for example, in JP-A-6-191872, the colored ink is applied in a state where the secondary layer is not cured or partially cured, and then the secondary layer and the colored ink are simultaneously cured. This increases the adhesion between the secondary layer and the colored layer.

[0004]

However, conventionally, in order to increase the adhesion between the coloring layer and the secondary layer,
The ultraviolet curable resin of the colored ink is sufficiently cured so as to have a degree of curing of about 100%, whereby the lubrication of the colored layer becomes too high, and when the optical fiber tape is used as a colored optical fiber core, Adhesion between the wire 5 and the resin for collective coating was deteriorated, and partial peeling of the optical fiber ribbon was sometimes caused.

[0005] The present invention has been made in view of such a situation, and in addition to the adhesiveness with the secondary layer of the optical fiber, the adhesiveness with the batch coating resin when the optical fiber ribbon is used. It is another object of the present invention to provide a colored optical fiber having a colored layer that is also excellent.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, by curing an ultraviolet curable resin of a colored ink so as to have a specific degree of curing, the colored layer and It has been found that the adhesiveness of the secondary layer of the optical fiber and the resin for batch coating of the optical fiber ribbon can be satisfied at the same time, and the present invention has been completed. That is, the object of the present invention is to provide a method for producing a colored optical fiber having a colored layer on the outermost layer of the optical fiber according to the present invention. It is achieved by a method for producing a colored optical fiber, characterized in that a resin is applied and the ultraviolet curable resin is cured so as to have a degree of curing of 80 to 90%.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. In the method for producing a colored optical fiber according to the present invention, the steps constituting the method are not particularly limited, and for example, the steps shown in FIG. 1 can be followed. That is, the optical fiber 2 provided with the primary layer and the secondary layer in advance is sent out from the delivery bobbin 1, and the colored ink is applied through the colored ink coating device 3, and then to the colored ink curing device 4 having an ultraviolet irradiation lamp. To cure the ultraviolet curable resin of the colored ink to pass through the colored optical fiber 5
Then, it is continuously manufactured by winding it on a winding bobbin 6.

The present invention relates to the above-described colored ink curing device 4.
The cured state of the ultraviolet curable resin of the colored ink is controlled by the method described above, and the ultraviolet curable resin is cured so as to have a degree of curing of 80 to 90%. If the degree of curing of the ultraviolet-curable resin is less than 80%, the adhesiveness with the resin for collective coating when forming the optical fiber ribbon is too good.
When separated into optical fiber strands, the colored layer is easily peeled off. On the other hand, if the degree of curing exceeds 90%, the lubricity of the colored layer is too high, and the adhesion to the resin for collective coating deteriorates.
Partial peeling of the optical fiber ribbon occurs.

[0009] The degree of curing of the ultraviolet curable resin can be adjusted by the irradiation amount or irradiation intensity of ultraviolet rays. FIG. 2 shows that the urethane acrylate resin generally used for the coloring ink of the colored optical fiber is cured by irradiating ultraviolet rays for the same time while changing the output of an ultraviolet irradiation lamp, and the degree of curing at that time is determined by a solvent extraction method. 2 shows a curing degree curve obtained by the measurement according to Example 1. From the figure, it can be seen that in order to obtain a degree of cure of 80 to 90%, the output of the ultraviolet irradiation lamp should be set to about 0.6 to 1.2 kW. Therefore, as shown in FIG. 2, a curing degree curve of the ultraviolet curing resin actually used is obtained in advance, and the ultraviolet irradiation lamp of the colored ink curing device 4 is set so that the curing degree is in the range of 80 to 90%. By adjusting the output, a colored layer desired by the present invention can be obtained.

The method of measuring the degree of curing of the ultraviolet curable resin may be, for example, an electric method for measuring volume resistivity, dielectric constant, dielectric power factor, or the like, or the mechanical strength of the cured product, in addition to the solvent extraction method. Various methods are possible, such as a method for measuring In this case, too, a curing degree curve as shown in FIG.
The output of the ultraviolet irradiation lamp so as to be 90% is obtained, and the actual coloring ink is cured. Therefore, in the present invention, the degree of cure is not defined by a specific measurement method, but is a value obtained by the adopted measurement method.

Further, in the present invention, all are optional except for the degree of curing of the ultraviolet curable resin of the colored ink. That is, the type and various physical properties (such as molecular weight) of the ultraviolet curable resin, the type and content of the coloring pigment, and other components such as a release agent can be appropriately selected. As an example, the coloring ink is 100 parts by weight of the urethane acrylate resin,
It is composed of 0.1 to 10 parts by weight of a coloring agent and 0.1 to 10 parts by weight of a release agent such as silicone or fluorine. The colored ink is generally applied so as to have a thickness of about 2 to 10 μm.

As described above, the colored optical fiber 5 having the colored layer in which the degree of curing of the ultraviolet curable resin is adjusted is made into an optical fiber ribbon by, for example, a resin for collective coating. The optical fiber ribbon has no partial peeling, and the colored layer does not peel when it is separated into individual optical fiber strands.

[0013]

The present invention will be further described below with reference to examples. A urethane acrylate resin is applied in a thickness of 37.5 μm on the outer peripheral surface of a single mode fiber having a diameter of 125 μm and cured to form a primary layer. Then, a urethane acrylate resin is applied on the outer peripheral surface to a thickness of 22.5 μm. And cured to form a secondary layer to produce an optical fiber. Then, using the production line shown in FIG. 1, the optical fiber 2 is first passed through the coloring ink coating device 3, and the urethane acrylate resin 100
A 5 μm-thick colored ink obtained by mixing 1.0 part by weight of titanium white (white pigment) and 0.5 part by weight of a silicone-based release agent to the parts by weight is applied. Thus, the ultraviolet curable resin of the coloring ink was cured. At the time of this curing, the linear velocity is 200 m / min.
When the output of the ultraviolet irradiation lamp was set to 0.8 kW, the degree of curing of the ultraviolet curable resin was 85% (colored optical fiber strand A), and the output of the lamp was set to 2.0 kW. The curing degree of the ultraviolet curing resin is 99% (colored optical fiber B), and the output of the lamp is 0.3 kW.
The curing degree of the ultraviolet-curable resin was 70% (colored optical fiber C). The degree of cure was measured by a solvent extraction method.

Next, the colored optical fiber strands A and B
And four pieces of the same C were collectively covered with a collective covering material made of urethane acrylate resin in a state of four pieces in parallel, thereby producing an optical fiber tape. Then, with respect to each optical fiber tape, the collective covering material was peeled off over 1 m to expose the colored optical fiber, and whether the colored layer was peeled at that time was visually inspected. When this peeling test was performed 50 times, the colored optical fiber strand A and the colored optical fiber strand B were
No peeling of the colored layer was observed at all in the optical fiber ribbon made of, while the colored layer was peeled 10 times in the optical fiber ribbon made of the colored optical fiber strand C. Further, when the presence or absence of partial peeling was examined for each of the optical fiber ribbons, no partial peeling was observed in the optical fiber ribbons composed of the colored optical fiber strand A and the colored optical fiber strand C. In the optical fiber ribbon made of the colored optical fiber strand B, partial peeling occurred at a plurality of locations.

[0015]

As described above, according to the present invention,
Provided is a colored optical fiber having a colored layer that has excellent adhesion to a resin for batch coating when forming an optical fiber ribbon, as well as adhesion to the secondary layer of the optical fiber. There is no partial peeling when the tape core is used, and the colored layer does not peel when the individual optical fibers are separated.

[Brief description of the drawings]

FIG. 1 is a schematic process diagram showing an embodiment of a method for producing a colored optical fiber according to the present invention.

FIG. 2 is a graph (curing degree curve) showing the relationship between the output of an ultraviolet irradiation lamp and the degree of curing of an ultraviolet curable resin.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Delivery bobbin 2 Optical fiber wire 3 Colored ink coating device 4 Colored ink curing device 5 Colored optical fiber wire 6 Winding bobbin

Claims (2)

[Claims] 1. A method for producing a colored optical fiber having a colored layer on the outermost layer of the optical fiber, comprising: applying an uncured ultraviolet curable resin containing a coloring pigment to the optical fiber; 80 to 9 of the ultraviolet curable resin
A method for producing a colored optical fiber, wherein the method comprises curing to a degree of cure of 0%. 2. The method according to claim 1, wherein the control of the degree of curing of the ultraviolet curable resin is performed by adjusting the output of an ultraviolet irradiation lamp.