JP2012027317A - Coated optical fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coated optical fiber which has excellent transmission characteristics and is superior in discrimination properties.SOLUTION: A coated optical fiber 11 comprises: a glass fiber 21; a coating layer 22 provided on the outer periphery of the glass fiber 21; a coloring layer 23 provided on a surface of the coating layer 22; and a ring mark 13 which is provided between the coating layer 22 and the coloring layer 23 and made of ring mark ink. A contact angle of water against the ring mark 13 after the coloring layer 23 is removed is 35°-52°.

Description

  The present invention relates to an optical fiber core wire in which a glass fiber is covered with a resin layer.

  In recent years, the demand for high-speed data communication has increased due to the rapid spread of the Internet, and the service of FTTH (Fiber To The Home) that installs an optical fiber to each home is expanding. As the construction of this FTTH system is accelerated, a multi-core loose tube cable is being studied. An optical fiber core wire can usually identify 12 cores by the color of the colored layer which colored the coating, for example. In order to further increase the number of cores, there is a need to identify each line other than the color of the colored layer.

  As an optical fiber having such discriminability, an optical fiber core wire in which a glass fiber is coated with a resin, a colored layer provided on the outer periphery, and between the optical fiber core wire and the colored layer are visually recognized from the outside. There is known an optical fiber colored core wire that is roughly configured from a marker portion that can be provided (see, for example, Patent Documents 1 to 6).

JP 2004-12680 A Japanese Patent Laid-Open No. 2004-77536 Japanese Patent Laid-Open No. 2004-77537 Japanese Patent Laid-Open No. 2004-77538 Japanese Patent Laid-Open No. 2004-77539 JP 2004-157193 A

In the above optical fiber core wire, the marking portion is provided between the coating layer and the colored layer. It does not disappear when wiping.
However, if the optical fiber core wire is left in a submerged environment or the like, the marker portion may absorb water and blisters (blowing) may occur at the interface with the coating layer or the colored layer. This is because, after applying the ink for the marker part, the ink of the ultraviolet curable resin for the colored layer is applied, and immediately after that, the ink of the marker part swells and absorbs water easily by irradiating with ultraviolet rays to be cured. This is probably because of this. If the water absorption of the ink in the marking part is large, blisters may grow in a submerged environment and cause minute bending distortion in the glass fiber.
As described above, the optical fiber core wire provided with the marking portion inside the colored layer can suppress the disappearance of the marking portion, but in a submerged environment, the glass fiber has a slight bending distortion caused by the blister, and the transmission characteristics are deteriorated. There was a risk of inviting.

  An object of the present invention is to provide an optical fiber core having good transmission characteristics and excellent discrimination.

The optical fiber core of the present invention capable of solving the above-mentioned problems is a glass fiber, a coating layer provided on the outer periphery of the glass fiber, a colored layer provided on the surface of the coating layer, and the coating layer And an optical fiber having an identification mark made of an identification ink provided between the colored layer and the colored layer,
The contact angle of water with respect to the identification mark after removing the colored layer is from 35 ° to 52 °.

  In the optical fiber core of the present invention, the resin component in the identification ink is preferably 25% by weight or less.

  According to the optical fiber core wire of the present invention, the identification mark identification ink is difficult to absorb water even when left in a submerged environment while ensuring good fixing between the identification mark and the coating layer, and blisters are generated. Alternatively, growth can be suppressed. For this reason, it is possible to eliminate a problem that a blister is generated in the identification mark to cause bending distortion in the glass fiber and cause deterioration in transmission characteristics. That is, it can have good transmission characteristics and excellent discrimination.

It is a figure which shows the example of embodiment of the optical fiber core wire which concerns on this invention, Comprising: (a) is a side view of an optical fiber core wire, (b) is the side view which expanded the identification part in an optical fiber core wire. . It is sectional drawing in the ring mark part which comprises the identification part of the optical fiber core wire of FIG. It is a figure which shows the example of the manufacturing method of the optical fiber core wire which concerns on this invention, Comprising: (a) is a side view of the optical fiber core wire in the application process of ring mark ink, (b) is in the application process of ring mark ink It is the side view to which the identification part was expanded. It is a side view which shows the wettability of the liquid with respect to the solid surface. It is a figure which shows the wettability of the liquid with respect to a solid surface, Comprising: (a) is a side view in case wettability is good, (b) is a side view in case wettability is bad.

Hereinafter, an example of an embodiment of an optical fiber core according to the present invention will be described with reference to the drawings.
As shown to Fig.1 (a), the optical fiber core wire 11 of this embodiment is provided with the some identification part 12 at predetermined intervals in the longitudinal direction.
As shown in FIG. 1B, the identification unit 12 has a plurality of ring marks (identification marks) 13 provided at equal intervals.

  As shown in FIG. 2, the optical fiber core wire 11 having the identification portion 12 has a coating layer 22 composed of a first coating 22a and a second coating 22b around a glass fiber 21 composed of a core 21a and a cladding 21b. Further, a colored layer 23 made of a colored resin is provided on the outer periphery thereof.

The ring mark 13 constituting the identification unit 12 is provided between the covering layer 22 and the colored layer 23. The ring mark 13 is provided so as to be visible from the outside through the colored layer 23.
The ring mark 13 is formed by providing a coating layer 22 on the glass fiber 21 sent out at a predetermined linear velocity to form an optical fiber core wire 11, and further spraying ring mark ink as identification ink by an ink jet printer device. By doing so, it is provided on the outer peripheral surface of the coating layer 22 along the circumferential direction.

  In the optical fiber core wire 11, the color of the colored layer 23 is different from that of the other core wires so that the core fiber can be distinguished from the other core wires. In addition, the number of identifiable hearts is increased by the combination of the color of the ring mark 13 and the color of the colored layer 23. Further, the number of identifiable hearts may be increased by using the arrangement of the ring marks 13 as an identification code.

  The ring mark 13 preferably covers a range A of 180 ° or more and less than 360 ° in the circumferential direction of the optical fiber core 11 in order to maintain the discriminability. Thereby, at the time of the terminal processing operation of the optical fiber core wire 11, the ring mark 13 of the identification unit 12 can be visually recognized and reliably identified from any circumferential direction.

  Moreover, as shown to Fig.1 (a), when maintaining the discriminability, it is preferable that the pitch P which is the space | interval of the identification part 12 in the longitudinal direction of the optical fiber core wire 11 is 100 mm or less, and 50 mm or less. It is more preferable that With such a pitch P, the ring mark 13 of the identification unit 12 can be visually recognized and reliably identified even if the length of the optical fiber core wire 11 that is fed out during the terminal processing operation is small. That is, it is possible to reduce the length of the optical fiber 11 that is drawn out when identifying the optical fiber 11 as much as possible.

  Moreover, as shown in FIG.1 (b), it is preferable that the width dimension W of one identification part 12 is 2 mm or more and 6 mm or less in order to maintain discriminability. When the width dimension W of one identification part 12 is less than 2 mm, it is difficult to visually recognize the identification part 12 and the discrimination is reduced. When the width dimension W of one identification part 12 exceeds 6 mm, the optical fiber core There is a risk that transmission loss as the line 11 increases.

  In order to maintain the identification, the identification unit 12 is preferably provided with 5 or more and 15 or less (seven in this embodiment) ring marks 13. For example, when the width dimension W of the identification unit 12 is 5 mm, the identification unit 12 is provided with less than five ring marks 13 (5 dot ejection of ring mark ink in a section of 5 mm). When the identification unit 12 is provided with 15 or more ring marks 13 (15 dots of ring mark ink is ejected in a 5 mm section) or more, the drawing speed of the optical fiber core 11 is reduced to increase the manufacturing cost. I will invite you.

  The ring mark ink (identification ink) used for the ring mark 13 is one having a resin component of 25% by weight or less. If the resin component is larger than this, the thickness of the ring mark 13 becomes as large as 3.0 μm or more, and the microbend loss increases. As the ring mark ink, it is preferable to use a fast-drying solvent-type dye ink. Examples of the solvent component include 13 to 90% methyl ethyl ketone (MEK), 10 to 35% methanol, or 3 to 7% or less. Those containing acetone or the like are preferred. Moreover, as a dye component of ring mark ink, what contains 1-10% or less chromium complex salt dye or 5-15% or less chromium metal-containing dye etc. is preferable. Further, the resin (polymer) component of the ring mark ink includes styrene (ST: Styrene), methyl methacrylate (MMA), butyl acrylate (BA), methacrylic acid (MAA), acrylic. Those containing a copolymer (molecular weight of about 8,000 to several tens of thousands, about 15 to 45% by weight) composed of monomers such as methyl acrylate (MA) are preferable. Further, ultraviolet curable ink, electron beam curable ink, or the like having a high curing speed may be used. Furthermore, a pigment system can be used as a pigment instead of a dye system.

Next, a manufacturing method of the optical fiber core wire 11 having the identification unit 12 will be described.
First, the coating layer 22 is formed by applying and curing a first coating 22a and a second coating 22b made of two types of ultraviolet curable urethane acrylate resins on the outer periphery of the glass fiber 21.

Next, while feeding the optical fiber core wire 11 at a predetermined linear velocity, as shown in FIGS. 3A and 3B, the ring mark ink 42 is intermittently ejected from the printer head 41 of the ink jet printer apparatus and applied. To do. Subsequently, a colored layer 23 made of an ultraviolet curable urethane acrylate ink is continuously applied to the outer periphery of the coating layer 22 and cured by irradiation with ultraviolet rays.
Thereby, the identification part 12 which has the some ring mark 13 between the coating layer 22 and the colored layer 23 is intermittently provided in the optical fiber core wire 11 with the predetermined pitch P in the longitudinal direction. Even if the colored layer 23 is applied to the outer periphery of the ring mark 13, it is preferable to use dark ink such as black as the ring mark ink 42 so that the ring mark ink 42 can be visually recognized through the colored layer 23.

  Further, in order to blow off the solvent of the ring mark ink 42 from the application of the ring mark ink 42 to the application of the colored layer 23, forced drying such as applying hot air after the application of the ring mark ink 42 is performed, or the colored layer It is preferable to lengthen the pass line in order to ensure the time until the application of 23.

  In FIG. 1B and FIG. 3B, a drop-shaped ring mark ink 42 is applied from above. As shown in FIGS. 1B and 3B, the ring mark ink (droplet) 42 applied on the optical fiber core 11 hangs down by its own weight and lies on the side of the optical fiber core 11. When viewed from the side, a triangular mark is attached.

  Examples of the inkjet printer apparatus that ejects the ring mark ink 42 to provide the ring mark 13 include the “EXCEL MVP series” manufactured by VIDEOJET, the “Image 9000 series” manufactured by IMAJE, and the “manufactured by Hitachi Industrial Equipment Systems Co., Ltd.” Commercial products such as “PXR series” and “MK-9000 series” manufactured by Keyence Corporation can be used. These ink jet printer apparatuses have no difference except that the ink composition is different, and there is no influence of the difference in the resin composition as long as the conditions of contact angle and thickness described later are satisfied.

The step of applying the ring mark ink 42 can be performed in a coloring step of applying and curing the colored ink that becomes the colored layer 23 on the outer periphery of the optical fiber core wire 11. That is, in the coloring process, before applying the colored ink that becomes the colored layer 23 by the coloring device, the ring mark ink 42 is sprayed and applied by the ink jet printer device installed in the coloring device, and then the colored layer 23 is continuously applied. Is applied and cured.
Alternatively, only the step of supplying the optical fiber core wire 11 that has been provided and stored with the ring mark 13 at a predetermined linear velocity and coating and curing the colored layer 23 on the optical fiber core wire 11 may be performed. it can.

  By the way, whether or not blisters (water blisters) occur in the above-described optical fiber core wire 11 in a flooded environment is affected by the water absorption of the ring mark ink 42 after the colored layer 23 is applied.

  When the degree of swelling of the ring mark ink 42 by the colored layer 23 is large, the link mark ink 42 of the ring mark 13 sandwiched between the coating layer 22 and the colored layer 23 easily absorbs water. Water accumulates at the interface and becomes a blister. When this blister becomes large, a minute bending strain is applied to the glass fiber 21, which causes problems such as an increase in transmission loss of the optical fiber core wire 11.

Therefore, in this embodiment, in order to improve the water absorption of the ring mark ink 42 after the colored layer 23 is applied, the “water contact angle” is used as an index.
The contact angle of water is determined by applying the ring mark ink 42 on the resin film constituting the second coating 22b of the coating layer 22, and further applying and curing the resin film constituting the colored layer 23 thereon, and then coloring the resin film. This is a contact angle when the layer 23 is peeled off and a water droplet is adhered to the ring mark ink 42.

  When the liquid is dropped on the solid surface, the droplet L is rounded on the surface of the solid S by its own surface tension, as shown in FIG. At this time, the following equation holds.

γ _S = γ _L · cos θ + γ _SL
Where γ _S : surface tension of the solid
γ _L : surface tension of liquid
γ _SL : Interfacial tension between solid and liquid

  This equation is called “Young's equation”, and the angle θ formed by the tangent of the droplet L and the surface of the solid S is called the “contact angle”. This contact angle θ can be easily measured with a commercially available contact angle meter. For example, “DM Series” manufactured by Kyowa Interface Chemical Co., Ltd., “DSA Series” manufactured by Sanyo Trading Co., Ltd., or the like can be used.

  As shown in FIG. 5A, when the degree of swelling is large, the water absorption is high and the contact angle θ is small. On the other hand, as shown in FIG. 5B, when the degree of swelling is small, the water absorption is low and the contact angle θ is large.

  In the present embodiment, the ring mark ink 42 is selected so that the contact angle θ of water with respect to the ring mark 13 composed of the ring mark ink 42 after removing the colored layer 23 is not less than 35 ° and not more than 52 °.

  The water contact angle θ at the ring mark 13 initially decreases with time. This is because water penetrates into the coating film of the ring mark ink 42. However, after a certain period of time, the decrease in the water contact angle θ stops and becomes a certain value. If this constant value is less than 35 °, the generation of blisters cannot be suppressed, and the generated blisters grow greatly. On the other hand, if the contact angle θ of water is 35 ° or more, the penetration of water is suppressed, and the generation or growth of blisters in the optical fiber core 11 placed in a flooded environment is suppressed. can do.

  In order to keep this water contact angle θ large, it is necessary to keep the ratio of the resin (polymer) component in the ring mark ink 42 to an appropriate amount. When the resin component in the ring mark ink 42 exceeds 25% by mass, the contact angle θ of water becomes less than 35 °, and blister resistance deteriorates. On the contrary, when the resin component is 25% by mass or less, the contact angle θ of water is 35 ° or more, and the growth of blisters is suppressed. However, in order to fix the ring mark ink 42 to the coating layer 22, a resin component is required to some extent. If the resin component of the ring mark ink 42 is the minimum resin component necessary for fixing the ring mark ink 42 to the coating layer 22, the contact angle θ of water at that time is 52 °.

  Therefore, considering the blister resistance and good fixability, the ring mark ink 42 has a resin component of 25% by weight or less, and the contact angle θ of water with respect to the ring mark 13 after the colored layer 23 is removed. It is preferable to use those having a angle of 35 ° or more and 52 ° or less.

  As a result, the optical fiber core 11 ensures good fixability with the coating layer 22 and causes bending distortion to the glass fiber 21 by blisters even when left in a submerged environment, thereby deteriorating transmission characteristics. It is possible to eliminate such inconveniences. That is, it can have good transmission characteristics and excellent discrimination.

On the polypropylene (PP) sheet, an ultraviolet curable resin serving as the second coating of the coating layer was applied by a spin coater, and an ultraviolet ray of about 100 mJ / cm ² was irradiated to prepare a base film having a thickness of about 30 μm.

On top of that, three types of ring mark inks A, B, and C to be ring marks are applied by a spin coater so as to have a thickness of 1 to 3 μm. The film was irradiated with ultraviolet rays of 500 mJ / cm ² to a thickness of about 20 μm.
From this state, the contact angle θ of water on the ring mark inks A, B, and C after peeling off the colored layer was measured. The water contact angle θ initially decreased with time, but after a certain amount of time, the decrease stopped and became a certain value.
In this measurement, the value 20 minutes after dropping water was defined as the “water contact angle”. As a result, it was found that the contact angle θ of water can be changed by selectively combining the inks of the colored layer and the ring mark inks A, B, and C. The measurement results and evaluation results are shown in Table 1.

(Measurement result)
As shown in Table 1, the contact angle θ of water after 20 minutes from dropping is 35 ° to 42 ° in Example 1 using the ring mark ink A, and in Example 2 using the ring mark ink B. In the comparative example using the ring mark ink C, the angle was 15 ° or less.

(Evaluation results)
The generation behavior of blisters when the optical fiber was immersed in warm water at 60 ° C. was examined.
In Example 1 in which the contact angle θ of water was 35 ° to 42 °, blisters were slightly generated 7 days after immersion in warm water, but the subsequent growth of blisters could not be confirmed, which was good.
In Example 2 in which the water contact angle θ was 45 ° to 52 °, the occurrence of blistering could not be confirmed. From this, it was found that Example 2 in which the water contact angle θ is 45 ° to 52 ° can further suppress the generation of blisters than Example 1 in which the water contact angle θ is 35 ° to 42 °.
In the comparative example in which the contact angle θ of water was 15 ° or less, a large blister was generated 24 hours after immersion in warm water, and then this blister grew.

  From the above, in the case of a combination of a colored layer and a ring mark ink with a water contact angle θ of 35 ° or more, the ring mark slightly swells even if the optical fiber core wire is immersed in warm water at 60 ° C. It was found that blistering can be suppressed to such an extent that no swelling can be confirmed even with a microscope. On the other hand, in the case of a combination of a colored layer and a ring mark ink in which the water contact angle θ is less than 35 °, if the optical fiber core wire is immersed in warm water at 60 ° C., the ring mark is formed in a short time (within 24 hours). It turns out that it swells greatly with water.

  It was also found that in order to keep the water contact angle θ at the ring mark large, it is necessary to keep the ratio of the resin (polymer) component in the ring mark ink at an appropriate amount. Further, it was found that when the resin component in the ring mark ink exceeds 25% by mass, the contact angle θ of water becomes less than 35 °, blister resistance deteriorates and blisters grow. On the contrary, when the resin component was 25% by mass or less, the contact angle θ of water was 35 ° or more, and it was found that blister growth was suppressed.

11: Optical fiber core wire, 13: Ring mark (identification mark), 21: Glass fiber, 22: Coating layer, 23: Colored layer, 42: Ring mark ink (identification ink), θ: Contact angle of water

Claims (2)

Identification comprising a glass fiber, a coating layer provided on the outer periphery of the glass fiber, a colored layer provided on the surface of the coating layer, and an identification ink provided between the coating layer and the colored layer An optical fiber having a mark,
The optical fiber core wire, wherein a contact angle of water with respect to the identification mark after removing the colored layer is 35 ° or more and 52 ° or less. The optical fiber core wire according to claim 1,
An optical fiber core, wherein the resin component in the identification ink is 25% by weight or less.

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