JPH03209207A - Optical fiber of multifiber tape - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a tape-type multi-core (two or more) optical fiber. [Prior art] Tape-type multi-core optical fiber (hereinafter sometimes abbreviated as tape embroidery) has been used for the purpose of increasing the density of optical fibers in optical cables and improving the efficiency of optical cable connection work. is widely used. As shown in Figure 1, the ribbon core is a single-core fiber made of quartz glass optical fiber 1, with a soft briny coating 2 made of ultraviolet curable resin, a hard secondary coating 3, a colored coating 4, etc. sequentially provided around the outer periphery of the optical fiber 1. A plurality of wires 5 (four wires in the illustrated example) are arranged in parallel, and a tape coating 6 made of ultraviolet curable resin or the like is applied all at once to the outer periphery to form a tape shape. Conventionally, such tape core wires have been required to have good (1) ability to remove the coating at once and (2) good ability to connect at once in order to facilitate connection work. These two characteristics are in a contradictory relationship with each other. For example, if the adhesive force at the interface between the optical fiber 1 and the primary coating 2 is small and the coating can be easily removed all at once, then the end of the optical fiber 1 is trimmed. After the fiber is cut, the cut end surface is likely to become uneven, which may result in increased splice loss or the inability to connect some optical fibers. On the other hand, if the adhesive force at the interface is large, the collective connectivity will be good, but the collective removability of the coating will be poor. For this reason, in the past, the adhesion force (at room temperature) at the interface was set to be sufficiently large, and when removing the coating all at once, the coating was applied at a high temperature (at room temperature).
A method has been adopted in which the coating is removed by heating the fiber to a temperature of about 0 to 100°C to reduce the shrinkage force of the coating and the adhesive force with the optical fiber. [Issue] By adopting this method, the problem of optical fiber end faces being uneven during splicing can be solved; However, the phenomenon of optical fibers protruding) was not always satisfactory. In addition, since ribbon fibers are used not only when gold optical fibers are connected all at once, but also when optical fibers are connected one by one, good single-fiber separation properties are also required. This single-core separability is in a contradictory relationship with the above-mentioned (1) removability of the coating at once. In other words, in order to improve single-fiber separability, it is necessary to weaken the adhesive force between the outermost coating of the single-filament wire and the tape coating, but if this adhesive force is weak, only the tape coating may peel off, or the tape coating may peel off. Otherwise, it becomes difficult to remove the single-core wire coating and the tape coating all at once. For these reasons, there has been a demand for the development of a tape core that can satisfy the characteristics of Φ to ■. [Means for solving the problem and their effects] When considering what factors the four characteristics mentioned above depend on, it is found that ∎ All-in-one coating removability, ∎ All-in-one connectability, and ∎ Protrusion are mainly related to the optical fiber and the optical fiber. It is greatly influenced by the adhesive strength with the coating. This adhesive strength depends not only on the adhesive force between the quartz glass and the Brimary resin, but also on the curing shrinkage force of the soft Brimary coating and the hard secondary coating. Therefore, as a parameter representing these combined effects,
A study was conducted using the ``coating pull-out force of a single-fiber wire.'' The remaining single-fiber separability is difficult to quantitatively evaluate because single-fiber separation is done manually, but it is mainly determined by the adhesive strength between the outermost coating of the single-fiber wire (usually a colored coating) and the tape coating. Therefore, we decided to examine single-fiber separability using the ``adhesive strength between the outermost coating resin of the single-fiber wire and the tape coating resin'' as an index. First, looking at the relationship between the "coating pull-out force of a single-filament wire" and the four characteristics mentioned above, the larger (smaller) this pull-out force, the worse (better) the collective removal of the coat.
■Bulk connectivity becomes better (worse), and ■Protrusion becomes smaller (larger). ■Single-core separability is not affected much. However, since the ability to remove the coating all at once can be improved by the heat treatment described above, it can be said that the larger the pulling force is, the better. Next, looking at the relationship between the "adhesive force between the outermost coating resin of the single-filament wire and the tape coating resin" and the four characteristics mentioned above, the larger (or smaller) this adhesive force is, the better the removability of the coating in one go.
■The protrusion becomes smaller (larger),
■Single-core separability gets worse (or better). ■Bulk connectivity is not affected much. Therefore, this adhesive force is a balance between ■■ and Φ. As a result of various prototype production and tests based on the above concept, we found that using a single fiber wire with a coating pull-out force of 0.5 kgf/30 mm or more, the outermost coating resin of the single fiber wire and the tape coating resin The inventors have discovered that by selecting the adhesive force in the range of 10 to 100 gf/cm, a tape core satisfying the above four properties can be obtained, and the present invention has been completed. The present invention will be described in detail below based on examples. [Example] A quartz-based optical fiber with an outer diameter of 125 μm was coated with a soft primary coating (outer diameter of 195 μm) and a hard secondary coating (outer diameter of 245 μm) using various ultraviolet curable urethane acrylate resins on the outer periphery of the fiber. Eight samples of coated core wires (each with different coating pull-out force) were made, and UV-curable ink for coloring was applied to the outer periphery of each coated wire to give an outer diameter of 255 mm.
A single fiber wire with μ is obtained. Furthermore, four core wires of each vehicle are arranged in parallel as shown in Figure 1, and the outer periphery of each core wire is coated with a hard UV-curable urethane acrylate resin in the form of a tape to a thickness of 0.
We prototyped a tape core with a length of 4 m and a width of 1.1 sm. The adhesive force between the ultraviolet curable ink on the outermost layer of the single fiber and the tape coating resin in these tape cores was 5 gf/cm. Figure 2 shows the results of investigating the relationship between the coating pull-out force of a single fiber and the optical fiber ejection characteristics for these ribbon cores. From this, it has become clear that if a single core wire with a coating pull-out force of 0.5 kgf/30 m or more is used, a tape core wire with no problems in terms of ejection characteristics can be obtained. The adhesion between the UV-curable ink and the tape coating resin, the pull-out force of the single-fiber wire, and the amount of protrusion were measured using the following methods. (4) Adhesive strength between ultraviolet curable ink and tape coating resin: On a layer of ultraviolet curable ink with a thickness of 5 to 8 μm that has been cured by irradiating 100 aJ/cm of ultraviolet rays, apply ultraviolet rays for tape coating. A curable resin was applied and then cured by irradiation with ultraviolet rays of LO*J/cm" to form a tape-coated resin layer with a thickness of 40 to 50 μm. For this sample, JIS-ZO237 “9”
The adhesive strength of both layers was measured using the 0° peeling method.
The peeling speed was 50 mm/gin, and the measurement atmosphere was 23±2°C and 50±10% RH. Medium》 Single-core wire sheath pull-out force: pull-out length 30 mm,
Pulling speed Love/@in, measurement atmosphere is 23±2
℃, 50±1O% IIH. The jig is Furukawa Electric ■
We used FITEL 5212B (trade name) manufactured by Manufacturer. IcI
Protrusion amount: Sample length is lm, -40℃~+60
℃ heat cycle (6 hrs/cycle) for 20
Measured after the cycle has passed. Next, with respect to the above-mentioned tape core wire, the ability to remove the coating at once was evaluated using a heating type coating removal device (heating temperature: approximately 85° C.). As a result, it was found that it was not possible to remove the coating all at once even with a tape core wire using a single core wire (with a coating pull-out force of 0.5 kgf/30 mm or more) that had no problem with ejection characteristics. A detailed study of the cause revealed that the adhesive force between the outermost layer of the single-fiber UV-curable ink and the tape coating resin was too low (5 gf/c) in consideration of single-fiber separability. It became clear that during removal, the shedding debris from the coating slipped on the interface between the outermost single-filament wire layer and the tape coating, and this caused the shedding debris to collapse, making it impossible to remove the coating all at once. By adjusting the &I1 precepts of the curable ink, we prepared various types of ink with different adhesion strengths to the tape coating resin, and made prototype tape core wires for each type to see if it was possible to achieve both single-core separation and one-shot coating removability. The results are shown in Table 1.
It is shown in In addition, each tape core wire has a coating pull-out force of 0.8.
A single core wire of kgf/30mm was used.

Table = 1 Judgment criteria for single-core separability ○: Single cores of 1 m length can be easily separated, and the tape coating attached to the single-core wire can be easily removed. ×: Colored coating peels off during single core separation. In the worst case, the single-core wire's coating peels off, exposing the optical fiber. Judgment criteria for the ability to remove the coating all at once: ○: The coating is removed over a length of 30 cm without any crumbling.
The coating can be removed all at once. ×: Unable to remove the coating all at once due to broken coating residue. From the above results, if the adhesive force between the ultraviolet curable ink and the tape coating resin is set in the range of lO to 100gf/(self),
It has become clear that a tape core can be obtained that satisfies both the simultaneous removal of the coating and the ability to separate single cores. Note that the resin coating the outermost layer of the single-filament wire is not limited to ultraviolet curing ink, but the same effect can be obtained as long as the adhesive strength between it and the tape coating resin is within the above range. Furthermore, the upper limit of the sheathing pulling force of a single-fiber wire is not particularly limited. For example, even if the single-fiber wire is about 3 kgf/30m+w, the outermost coating resin of the single-fiber wire and the tape coating resin are within the above range. If the tape core wire has an adhesive strength of
By using a heated coating remover (80-100°C), it is possible to remove the coating all at once. [Effects of the Invention] As explained above, according to the present invention, it is possible to create a tape-type multi-core optical fiber that satisfies the following properties: (1) collective removability of coating, (2) collective connectability, (2) protrusion, and (2) single fiber separability. Obtainable.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view showing an example of a tape-type multi-core optical fiber, and Figure-2 is a graph showing the relationship between the pull-out force of the single fiber sheath and the amount of optical fiber protrusion in the tape-type multi-core optical fiber. It is. 1: Optical fiber 2: Brimary coating 3: Secondary coating 4: Colored coating 5: Single core &91 6: Tape coating diagram-1 6

Claims (1)

[Claims] 1. In a tape-type multi-core optical fiber core formed by arranging a plurality of single fibers having a resin coating on the outer periphery of a quartz glass optical fiber in parallel, and applying a resin tape coating to the outer periphery at once. , the pull-out force of the single-core wire is 0.5k.
gf/30 mm or more, and the adhesive force between the outermost layer coating resin of the single-filament wire and the tape coating resin is 10 to 100 gf/c.
A tape-type multi-core optical fiber, characterized in that the fiber core is in the range of m.