JP2004233662A - Coated optical fiber ribbon - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To quantitatively grasp the curabilities of a colored layer surface of a colored primary coated optical fiber and a coating layer surface of a primary coated optical fiber, and to improve single fiber isolation by exactly setting correlative conditions of the two. <P>SOLUTION: A colored primary coated optical fiber (15) is used for which the condition of α<β is satisfied by a contact angle (α) measured when a plurality of primary coated optical fibers (3) are arranged and a water droplet (W) is put on the surface, and a contact angle (β) measured when a plurality of colored primary coated optical fibers (5) are arranged and a water droplet (W) is put on the surface, and a plurality of such colored primary coated optical fibers (15) are arranged and integrated by a batch coating layer (16) to fabricate the objective coated optical fiber ribbon (10). <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical fiber ribbon.
[0002]
[Prior art]
In general, there is a so-called optical fiber ribbon having a plurality of optical fibers. Such an optical fiber tape core wire uses a plurality of optical fiber wires each having a coating layer formed by curing an ultraviolet curable resin composition on the outer peripheral surface of a single-core optical fiber. In order to identify each other when using, the outer peripheral surface of each optical fiber strand, constituting an optical fiber dyed wire formed a colored layer by curing the ultraviolet curable resin composition containing a coloring agent, A plurality of these optical fiber dye lines are arranged in parallel, and the whole is integrally formed by a collective coating layer formed by curing an ultraviolet curable resin composition.
[0003]
As described above, an optical fiber ribbon, which is formed by arranging a plurality of optical fiber dye lines each having a colored layer formed on the outer peripheral surface of the optical fiber strand, is used as an optical fiber dye line when used as a communication line. Are separated one by one. That is, the optical fiber ribbon is used for actual use as a communication line by separating the optical fiber pigmented wire from the optical fiber pigmented wire by a single layer and separating the optical fiber pigmented wire. Therefore, the optical fiber ribbon is required to be able to easily perform single-core separation, that is, to have good single-core separation properties.
[0004]
However, for example, when the adhesion between the colored layer on the surface of the optical fiber dyed wire and the outer coating layer is stronger than the adhesion between the coating layer on the surface of the optical fiber and the colored layer on the outside, single-core separation occurs. Since the colored layer is peeled off from the surface of the dyed optical fiber when performing the process, the single-fiber separation is easily performed while preventing such inconveniences as peeling of the colored layer, etc. Have been proposed for the material property values of the respective UV-curable resin compositions forming the coating layer, the colored layer and the collective coating layer.
[0005]
[Patent Document 1]
JP-A-2002-90588
[Patent Document 2]
JP 2002-221647 A
[Problems to be solved by the invention]
The inventors of the present invention have studied and found that the single-core separability of the optical fiber ribbon largely depends on the curability of the cured product surface when the ultraviolet curable resin composition is cured. For example, when applying the liquid UV-curable resin composition to be the next cured layer on the surface of the cured product obtained by curing the UV-curable resin composition, the unreacted UV-curable resin component is applied to the surface of the cured product. When remaining, when irradiated with ultraviolet rays to cure the applied liquid ultraviolet curable resin composition, at the interface between the two, the unreacted ultraviolet curable resin component on the surface of the cured product and the applied ultraviolet curable resin The UV-curable resin of the resin composition reacts and adheres. The phenomenon that depends on the curability of the surface of the cured product is only the curability of the surface of the formed cured product, regardless of whether the ultraviolet curable resin composition forming the cured product contains a colorant or not. Depends on Therefore, in order to easily perform single-core separation while preventing peeling of the colored layer, the curability of the colored layer surface of the optical fiber dyeing wire is important, and the curing of the coating layer surface of the optical fiber is also important. Gender and correlation conditions are particularly important.
[0008]
However, Patent Document 1 and Patent Document 2 do not refer to the curability of the surface of the cured product when the ultraviolet-curable resin composition is cured, and therefore, an optical fiber based on the curability of the surface of the cured product. There was a problem that it was not possible to discuss the single-core separability of the tape.
[0009]
In addition, the inventors of the present invention have found that it is effective to use a contact angle using a water droplet as an index indicating the curability of the surface of a cured product. Patent Literature 1 and Patent Literature 2 describe a contact angle using a droplet. However, the reason that these patent documents use the contact angle by the droplet is that the contact angle when the droplet of the second resin composition is arranged on the cured product of the first resin composition is within a predetermined range. When satisfied, the second resin composition is easy to penetrate even minute irregularities on the surface of the cured product of the first resin composition, and the second resin composition can be more uniformly applied without unevenness. It is not an index indicating the curability of the cured product surface.
[0010]
Moreover, when the contact angle is measured by dropping a droplet of the ultraviolet curable resin composition to be the next cured layer on the surface of the cured product obtained by curing the ultraviolet curable resin composition, the contact angle is determined. What is obtained is not the surface state of the cured product, but the viscosity and surface tension of the droplet.Therefore, temporarily, the contact angle measured using the droplet of the ultraviolet-curable resin composition to be the next cured layer, Even if an attempt is made to use it as an index indicating the curability of the surface of the cured product, the index does not accurately reflect the curability. In addition, the ultraviolet curable resin composition used for optical fibers, including those containing a coloring agent, has a good wettability so that application to a wire can be performed at high speed. It is inevitable that the change in the surface state of the cured product must be measured, even if the change in the surface state of the cured product is to be determined from the change in the contact angle. Is difficult to observe.
[0011]
Further, in Patent Document 1 and Patent Document 2, the surface condition is evaluated using a cured product obtained by applying and curing an ultraviolet curable resin composition on a sheet. It cannot be applied to a dye line, and there is a problem that it is difficult to evaluate the surface state using an actual optical fiber dye line.
[0012]
An object of the present invention is to quantitatively grasp the curability of the colored layer surface of an optical fiber dyed wire, and the curability of the coating layer surface of an optical fiber, by eliminating the above-mentioned problems of the related art. It is another object of the present invention to provide an optical fiber ribbon that can improve single-core separation by properly setting a correlation condition between the two.
[0013]
[Means for Solving the Problems]
The present invention solves the above-mentioned problems, and the invention according to claim 1 is a method in which an ultraviolet curable resin composition is cured on an optical fiber to form a coating layer on the outer peripheral surface of the optical fiber. By arranging a plurality of optical fiber dye lines having a colored layer formed by curing an ultraviolet curable resin composition containing an agent, and integrally forming a collective coating layer formed by curing the ultraviolet curable resin composition In the optical fiber ribbon, a plurality of optical fiber strands are arranged, a contact angle α measured by arranging water droplets on the surface thereof, and a plurality of optical fiber dyed wires are measured. The contact angle β measured by arranging and arranging water droplets on the surface is an optical fiber ribbon formed by using an optical fiber coloring wire satisfying the condition of α <β.
[0014]
According to a second aspect of the present invention, in the first aspect of the present invention, a plurality of the optical fiber strands are closely arranged at a density of 0.95 or more, and a contact angle is measured by arranging a water droplet on the surface. α and the contact angle β measured by arranging a plurality of fibers in the state of the dyed optical fiber line tightly at a density of 0.95 or more and arranging water droplets on the surface thereof, satisfying the condition α <β. This is an optical fiber ribbon obtained by arranging a plurality of fiber dye lines and integrating them by the collective coating layer.
[0015]
According to a third aspect of the present invention, in the first or second aspect of the present invention, a plurality of the optical fiber strands are arranged, and water droplets are arranged on the surface of the plurality of optical fiber strands. A plurality of contact angles α measured in a vertical plane along the optical fiber dye line are arranged, water droplets are arranged on the surface thereof, and a vertical direction along the longitudinal direction of the optical fiber dye line is arranged. The contact angle β measured in the plane is an optical fiber ribbon obtained by arranging a plurality of dyed optical fiber wires satisfying the condition of α <β and integrating them by the collective coating layer.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic sectional view showing an embodiment of an optical fiber ribbon according to the present invention. The optical fiber ribbon 10 is obtained by curing an optical fiber 11 with an ultraviolet curable resin composition. A plurality of optical fiber coloring lines 15 having a coloring layer 14 formed by curing an ultraviolet curable resin composition containing a coloring agent are arranged in parallel on the outer peripheral surface of the optical fiber 13 having the coating layer 12 formed thereon. , And are integrally formed by a collective coating layer 16 formed by curing an ultraviolet curable resin composition.
[0017]
The optical fiber ribbon 10 has a contact angle α measured by arranging a plurality of optical fibers 13 in the state of an optical fiber 13 and arranging a water droplet on the surface thereof, and a state of the optical fiber dyeing line 15. Are arranged, and a contact angle β measured by arranging a water droplet on the surface thereof is configured using an optical fiber dye line satisfying the condition of α <β.
[0018]
In addition, a plurality of wires in the state of the optical fiber strand 13 are closely arranged at a density of 0.95 or more, and a contact angle α measured by arranging a water droplet on the surface thereof, and a plurality of wires in the state of the optical fiber dyed wire 15 are measured. The books are closely arranged at a density of 0.95 or more, and a plurality of optical fiber dye lines satisfying the condition of α <β are arranged with a contact angle β measured by arranging a water droplet on the surface. It is integrated.
[0019]
Further, a plurality of optical fiber strands 13 are arranged, and a contact angle α measured in a vertical plane along the longitudinal direction of the optical fiber strand with water drops placed on the surface thereof, A plurality of lines 15 are arranged, and a contact angle β measured in a vertical plane along the longitudinal direction of the optical fiber dye line with a water droplet disposed on the surface thereof satisfies the condition of α <β. A plurality of optical fiber dye lines are arranged and integrated by a collective coating layer 16.
[0020]
FIG. 2 shows the arrangement of the optical fiber wires 3 and the contact angle in order to measure the contact angle by arranging a water drop on the surface of the optical fiber wire 13 (this is represented as the optical fiber wire 3). FIG. 3 is an explanatory diagram of the measuring method. FIG. 3 shows a state of the optical fiber dyed line 15 (this is referred to as an optical fiber dyed line 5). Therefore, FIG. 4 is a diagram illustrating a method of arranging the optical fiber dyed wires 5 and a method of measuring a contact angle. FIG. 4 shows a contact according to the density when a plurality of the optical fiber wires 3 and the optical fiber dyed wires 5 are arranged. It is a table | surface which shows the result of having investigated how the angle changes.
[0021]
This embodiment will be specifically described with reference to FIGS. 2 to 4. The optical fiber 1 is coated with 2 L of a liquid ultraviolet curable resin composition, and the optical fiber 1 is placed in an atmosphere in which the oxygen concentration can be adjusted. By irradiating ultraviolet rays to the ultraviolet-curable resin composition 2L while adjusting the oxygen concentration and the amount of ultraviolet irradiation, the ultraviolet-curable resin composition 2L is cured to form a cured product 2S, that is, the coating layer 2, This forms the optical fiber 3 (see FIGS. 2B and 2C).
[0022]
Further, a liquid ultraviolet curable resin composition 4AL containing the colorant A is applied to the outer peripheral surface of the optical fiber 3 and the optical fiber 3 is placed in an atmosphere in which the oxygen concentration can be adjusted. By irradiating the ultraviolet curable resin composition 4AL containing the colorant A with ultraviolet rays while adjusting the concentration and the amount of ultraviolet irradiation, the ultraviolet curable resin composition 4AL is cured and the cured product 4AS containing the colorant A, that is, The coloring layer 4 is formed, and thereby the optical fiber coloring line 5 is formed (see FIGS. 3B and 3C).
[0023]
In order to measure the contact angle α by dropping a water droplet W of ion-exchanged water on the surface of the optical fiber 3 thus obtained, a plurality of optical fiber 3 are arranged. Similarly, in order to measure the contact angle β by dropping a water droplet W of ion-exchanged water on the surface of the optical fiber dye line 5, a plurality of the optical fiber dye lines 5 are arranged. At this time, if the diameter of the optical fiber strand 3 and the dyed-colored optical fiber 5 is d, and if n pieces of the optical fiber strands 3 and the dyed-colored optical fiber 5 are arranged along the length L, the density ρ is It can be expressed as ρ = nd / L (see FIGS. 2A and 3A). FIG. 4 shows the results of measuring the contact angles α and β while changing the density ρ.
[0024]
As shown in FIG. 4, when the density ρ at which the optical fiber strands 3 and the dyed-colored optical fibers 5 are arranged decreases, a gap is generated between the adjacent optical fiber strands 3 and the dyed-colored optical fibers 5. The water droplet W flows through the gap, and the contact angles α and β become unstable. For this reason, when the density ρ for arranging the optical fiber 3 and the dyed fiber 5 is 0.95 or more (ρ ≧ 0.95), the contact angles α and β of the water droplet W can be measured stably. . The contact angles α and β shown in FIG. 4 are obtained by examining the relationship between the optical fiber 3 and the density ρ at which the optical fiber dyed wires 5 are arranged. Does not make sense.
[0025]
Therefore, based on this result, a plurality of optical fiber strands 3 are actually closely arranged at a density of 0.95 or more (ρ ≧ 0.95). Then, a droplet W of ion-exchanged water is dropped on the surface, and the contact angle α is measured. Similarly, a plurality of optical fiber dye lines 5 are closely arranged at a density of 0.95 or more (ρ ≧ 0.95). Then, a droplet W of ion-exchanged water is dropped on the surface, and the contact angle β is measured.
[0026]
In general, the measurement of the contact angle α and the contact angle β of the water droplet W is performed on a flat surface (flat surface). However, a non-flat surface such as a surface on which the optical fiber wires 3 and the optical fiber dye lines 5 are arranged. (An anisotropic surface), it is possible to measure the contact angles α and β. At this time, the spread of the water droplet W is different between the longitudinal direction of the optical fiber strand 3 and the optical fiber dyed wire 5 and the direction orthogonal thereto, and thus the water droplet W is in a vertical plane along any one of the directions. Can be measured. Among them, the longitudinal direction of the optical fiber strand 3 and the optical fiber dyeing line 5 has a larger spread of the water droplet W than the direction orthogonal thereto, but is less affected by the anisotropic shape. It is preferable to measure the contact angle α and the contact angle β of the water droplet W in a vertical plane V along the longitudinal direction of the optical fiber wire 3 and the optical dyed wire 5. More specifically, the contact angle α of the water droplet W is measured in a vertical plane V passing through the center axis of one optical fiber 3 near the center of the water droplet W (see FIGS. 2B and 2C). Similarly, the contact angle β of the water droplet W is measured in a vertical plane V passing through the central axis of one optical fiber coloring line 5 near the center of the water droplet W (see FIGS. 3B and 3C). Such measurement of the contact angle α and the contact angle β can be performed using an appropriate commercially available contact angle meter.
[0027]
FIG. 5 shows a plurality of types of optical fiber wires 3 having a diameter of 0.245 mm in which various coating layers 2 are formed on an optical fiber 1 at a density ρ (ρ ≧ 0.95) of 0.95 or more. A water drop W of ion-exchanged water is dropped on the surface thereof, and the contact angle α of the water drop W measured in a vertical plane V along the longitudinal direction of the optical fiber 3 (see FIGS. 2B and 2C). 3) is a table showing the measurement results.
[0028]
FIG. 6 shows that the outer peripheral surface of each optical fiber 3 used in FIG. 5 is adjusted in an oxygen concentration adjustable atmosphere in an oxygen concentration adjustable atmosphere, and the irradiation amount of the ultraviolet light is adjusted. Meanwhile, a plurality of types of optical fiber dyeing wires 5 having a diameter of 0.250 mm on which various colored layers 4 containing the colorant A were formed were all formed at a density ρ (ρ ≧ 0.95) of 0.95 or more. The water droplets W of the ion-exchanged water are dropped on the surface thereof, and the contact angle β of the water droplets W measured in the vertical plane V along the longitudinal direction of the dyed optical fiber 5 (FIGS. 3B and 3C) 4) is a table showing the measurement results of (2). In addition, the single-core separation of the optical fiber tape core wire 10 prepared (prototype) using each of the optical fiber dye lines 5 as the optical fiber dye line 15 is performed, and the colored layer 14 of the optical fiber dye line 15 is separated. 4 is a table showing the results of observing the presence or absence of peeling (single-fiber separation). Here, the single-core separability was evaluated as follows: 50 cm of each optical fiber ribbon 10 was single-core separated, and when there was a portion where the colored layer 14 was peeled off during the work, x was determined. When there is no case, it was marked as 〇.
[0029]
In general, it is said that the curability of the surface of a cured product made of an ultraviolet-curable resin composition has a positive correlation with the amount of ultraviolet irradiation and a negative correlation with the oxygen concentration.
[0030]
As shown in FIG. 6, as far as the contact angle β of the water droplet W can be seen, there is a correlation with the irradiation amount of ultraviolet rays and a correlation with the oxygen concentration, and furthermore, a positive correlation with the irradiation amount of ultraviolet rays and a negative correlation with the oxygen concentration. Therefore, the curability of the surface of the cured product (colored layer 4) made of the ultraviolet curable resin composition is correlated with the contact angle due to the water droplet. That is, when the contact angle β due to the water droplet is large, the surface hardened state of the colored layer 4 is good, while when the contact angle β due to the water droplet is small, the surface hardened state of the colored layer 4 is poor. In addition, the surface hardening state of the colored layer 4 can be evaluated according to the magnitude of the contact angle β due to the water droplet. Since the coating layer 2 of the optical fiber 3 is also a cured product made of the ultraviolet curable resin composition, similarly, the surface hardening state of the coating layer 2 can be evaluated according to the magnitude of the contact angle α due to the water droplet. .
[0031]
The reason why there is a correlation between the curability of the surface of the cured product made of the ultraviolet curable resin composition and the magnitude of the contact angle due to water droplets is not clear, but since the surface energy changes depending on the cured state of the surface of the cured product. it is conceivable that. Generally, since the contact angle is small on a high energy surface and the contact angle is large on a low energy surface, the better the surface curing state of the cured product is, the lower the surface energy is, and as a result, the contact angle due to water droplets is reduced. It is thought to be larger. Therefore, it is clear that the measured value of the contact angle by the water droplet can be used as an index indicating the curability of the surface of the cured product (the coating layer 2 and the colored layer 4) made of the ultraviolet curable resin composition.
[0032]
As is apparent from FIG. 6, in the case of the optical fiber 3 (A) having the coating layer 2 having a contact angle α of 58 ° due to water droplets, the contact angle β due to water droplets on the surface of the colored layer 4 is 69 ° or more. , The single-core separability is 〇, and the single-core separability is × when the contact angle β with a water droplet is 40 ° or less. Also, in the case of the optical fiber 3 (B) having the coating layer 2 having a contact angle α of 48 ° due to water droplets, if the contact angle β due to water droplets on the surface of the colored layer 4 is 69 ° or more, single-core separation is performed. When the property is Δ and the contact angle β due to a water droplet is 40 ° or less, the single-core separation property is ×. In the case of the optical fiber 3 (C) having the coating layer 2 having a contact angle α of 36 ° due to water droplets, if the contact angle β due to water droplets on the surface of the colored layer 4 is 40 ° or more, the single-core separation property is obtained. Is Δ, and when the contact angle β due to the water droplet is 20 °, the single-core separation property is ×. Further, in the case of the optical fiber 3 (D) having the coating layer 2 having a contact angle α of 30 ° due to water droplets, if the contact angle β due to water droplets on the surface of the colored layer 4 is 40 ° or more, the single-core separation is performed. When the property is 〇 and the contact angle β with a water droplet is 20 °, the single-core separation property is ×.
[0033]
From these results, it is found that the optical fiber 3 having the coating layer 2 in which the contact angles α and β by water droplets satisfy the condition of α <β is used as the optical fiber 13 and the optical fiber having the coloring layer 4 formed thereon. The optical fiber ribbon 10 in which the dye line 5 is formed as the optical fiber dye line 15 is colored in the optical fiber dye line 15 in comparison with the contact angle α of the water droplet on the surface of the coating layer 12 of the optical fiber strand 13. Since the contact angle β due to water droplets on the surface of the layer 14 is larger (α <β), the curability of the surface of the colored layer 14 is better than the curability of the surface of the coating layer 12, Since the adhesion between the coloring layer 14 of the optical fiber coloring wire 15 and the collective coating layer 16 outside the coloring layer 14 is weaker than the adhesion between the coating layer 12 of the optical fiber strand 13 and the coloring layer 14 outside the same, single-core separation can be performed. At the time of carrying out, it attaches from the surface of Peeling of the color layer 14 is prevented beforehand and surely.
[0034]
Among the optical fiber tape cores 10 configured as described above, an ultraviolet curable resin containing a colorant A that does not reduce the contact angle on the surface of the cured product even when the amount of ultraviolet irradiation is low and the oxygen concentration is high. The composition 4AL is selected and used as the coloring layer 14 of the optical fiber dyeing line 15, and the ultraviolet curable resin composition 2L, which does not decrease the contact angle on the surface of the cured product even when the amount of ultraviolet irradiation is low and the oxygen concentration is high, is used. By selecting and using it as the coating layer 12 of the optical fiber 13, it becomes possible to easily manufacture the optical fiber ribbon 10 having good single-core separability.
[0035]
【The invention's effect】
As described above, the present invention cures an ultraviolet-curable resin composition containing a colorant on the outer peripheral surface of an optical fiber strand having a coating layer by curing the ultraviolet-curable resin composition on an optical fiber. By arranging a plurality of dyed optical fiber dye lines having a colored layer formed thereon, and in an optical fiber tape core wire integrated by a collective coating layer formed by curing the ultraviolet curable resin composition, The contact angle α measured by arranging a plurality of pieces in the state and arranging water droplets on the surface thereof, and the contact angle β measured by arranging a plurality of things in the state of optical fiber dye lines and arranging water drops on the surface thereof Since the optical fiber ribbon was configured using an optical fiber dyed wire satisfying the condition of α <β, the contact angle using a water droplet was measured to determine the color layer surface of the optical fiber dyed wire. Hardening , And the curability of the coating layer surface of the optical fiber can be quantitatively grasped, whereby the curing property of the coloring layer surface of the optical fiber dyed wire and the curing of the coating layer surface of the optical fiber can be determined. By properly setting the correlation condition with the gender, there is an effect that the single-core separability can be improved.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view showing an embodiment of an optical fiber ribbon according to the present invention.
FIG. 2 is an explanatory diagram of a method of arranging optical fiber strands and a method of measuring a contact angle.
FIG. 3 is an explanatory diagram of a method of arranging optical fiber dye lines and a method of measuring a contact angle.
FIG. 4 is a table showing a result of examining how a contact angle changes depending on a density when a plurality of optical fiber wires and dyed optical fiber wires are arranged.
FIG. 5 is a table showing measurement results of a contact angle α of an optical fiber.
FIG. 6 is a table showing a measurement result of a contact angle β of an optical fiber dyed wire and an observation result of single-core separation property (presence or absence of peeling of a colored layer).
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Optical fiber ribbon 1,11 Optical fiber 2,12 Coating layer 3,13 Optical fiber wire 4,14 Coloring layer 5,15 Optical fiber coloring line 16 Collective coating layer W Water droplet α, β Contact angle ρ Density V Vertical plane

Claims (3)

A light having a colored layer formed by curing a UV curable resin composition containing a colorant on the outer peripheral surface of an optical fiber having a coating layer formed by curing the UV curable resin composition on the optical fiber. A plurality of fiber dye lines are arranged, and in an optical fiber tape core integrated by a collective coating layer formed by curing an ultraviolet curable resin composition,
A plurality of the optical fiber strands are arranged, a contact angle α measured by arranging a water droplet on the surface thereof, and a plurality of the optical fiber dye lines are arranged, and a water droplet is arranged on the surface. An optical fiber ribbon comprising an optical fiber dyed wire that satisfies the condition of α <β, wherein the contact angle β measured by the measurement is α <β. A plurality of wires in the state of the optical fiber are closely arranged at a density of 0.95 or more, a contact angle α measured by arranging a water droplet on the surface, and a plurality of wires in the state of the dyed optical fiber. A plurality of optical fiber dye lines satisfying the condition of α <β are arranged in a line with a density of 0.95 or more and a contact angle β measured by arranging a water drop on the surface, and integrated by the collective coating layer. The optical fiber ribbon according to claim 1, wherein: A plurality of the optical fiber strands are arranged, and a contact angle α measured in a vertical plane along a longitudinal direction of the optical fiber strand by disposing a water droplet on the surface thereof, and the optical fiber dyed wire. And a contact angle β measured in a vertical plane along the longitudinal direction of the optical fiber dye line with water droplets arranged on the surface thereof, and an optical fiber satisfying the condition of α <β 3. The optical fiber ribbon according to claim 1, wherein a plurality of coloring wires are arranged and integrated by the collective coating layer.

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