JPH02118608A - Coated optical fiber tape - Google Patents

Abstract

PURPOSE:To reduce the change of the secular change transmission loss of an optical fiber by composing a tape coating of an ultraviolet radiation curing resin to which a silica micropowder is added. CONSTITUTION:A tape coating 6 executed to the outer circumference of an aggregate in a coated optical fiber tape 10 is composed of the ultraviolet radiation curing resin to which a silica micropowder 7 is added. When the grain diameter of the added silica powder 7 is too large, an adverse effect is generated to the strength of the resin, and when it is too small, the problem such as the increase of a viscosity is generated. When the added quantity of the silica power 7 is too large, the curability of the resin is made bad, and when it is too small, a sufficient adding effect cannot be obtained. Thus, due to an expansion stress applied to the tape coating layer 6, the deterioration of the secular change transmission characteristic generated to the optical fiber can be reduced.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an optical fiber in which a coating layer is applied in the form of a tape around the outer periphery of an assembly in which a plurality of optical fibers are arranged adjacently in a line. This invention relates to optical fiber ribbons, and particularly to improvements in the structure of optical fiber ribbons.

[Conventional technology]

FIG. 2 shows a cross-sectional structure of a four-core optical fiber tape, which is an example of this type of conventional optical fiber tape. A four-core optical fiber tape core wire 20 in which a tape coating 3 is collectively applied to the outer periphery of an assembly in which four optical fibers each having an optical fiber coating 2 applied to the outer periphery of a glass fiber 1 are arranged in a row adjacent to each other. It is.

Usually, as with the optical fiber coating 2, the tape coating 3 of the optical fiber ribbon is made of ultraviolet curable resin, which is advantageous in terms of productivity. As an example of an optical fiber tape coated with this ultraviolet curable resin, an optical fiber tape coated with an optical fiber having a lateral pressure characteristic superior to that of an optical fiber placed in the center is placed at both ends. has been proposed (for example, in Japanese Patent Application Laid-open No. 6
Publication No. 2-220913. ).

Furthermore, a method for producing this type of optical fiber ribbon using a step of applying tape coating with an ultraviolet curable resin has also been proposed (for example, Japanese Patent Application Laid-Open No. 6163810).

[Problem to be solved by the invention]

In the conventional optical fiber tape cable having the structure illustrated in FIG. 2, when the tape coating is applied, the tape coating layer is subjected to elongation strain in the longitudinal direction of the tape cable. The tape coating layer shrinks over time. As a result, there is a problem in that shrinkage strain is applied to the optical fiber, resulting in deterioration of transmission characteristics.

In addition, when applying tape coating, the elongation strain applied to the tape coating layer increases as the manufacturing speed of the tape core increases. Therefore, in order to further improve productivity, it is necessary to There is a need to reduce deterioration of transmission characteristics over time.

The present invention is characterized by the elongation strain applied to the tape coating layer.
The object of the present invention is to provide an optical fiber tape wire that reduces deterioration of transmission characteristics over time that occurs in optical fibers.

[Means to solve problems]

In order to achieve the above object, the present invention has a tape-like structure in which a tape coating is applied all at once to the outer periphery of an assembly in which a plurality of optical fibers or optical fiber strands each having a protective coating are arranged adjacently in a row. The optical fiber core wire is characterized in that the tape coating applied to the outer periphery of the aggregate is made of an ultraviolet curable resin to which fine silica powder is added.

[For production]

In the optical fiber ribbon of the present invention, since the tape coating is filled with fine silica powder, shrinkage over time of the tape coating subjected to elongation strain is significantly reduced.

In general, it is common practice to add fillers to resins in order to improve their dimensional stability.
"New Epoxy Resin" (edited by Hiroshi Kakiuchi, Shokodo), page 294 lists the types and properties of inorganic fillers. Dimensional stability here usually means that the coefficient of linear expansion is small.

In contrast, in the present invention, even when the coating material that has been subjected to elongation strain during the coating process shrinks over time, as in the case of tape coating of optical fiber tape, the use of a filler allows the coating material to shrink over time. This was done with the focus on the ability to reduce shrinkage.

When a filler is added to a tape coating made of an ultraviolet curable resin, which is most commonly used, there is a problem in that the curability of the coating deteriorates because the additive absorbs ultraviolet rays. In order to solve this problem, the present invention actually mixes powders of various inorganic materials into resin, compares their hardenability, and finds that it is optimal to add and fill the silica fine powder that makes up 5i02. revealed.

Figure 3 shows an example of silica powder and titanium oxide (Ti
02) The relationship between the amount added and the cured film thickness when the powder is added or mixed into the ultraviolet curable resin is shown. Here, the cured film thickness is the surface of the uncured ultraviolet curable resin. That is,
This indicates that the smaller the value of the cured film thickness, the greater the absorption of ultraviolet light and the worse the curability.

As is clear from FIG. 3, silica powder exhibits little decrease in cured film thickness due to an increase in the amount added, indicating that it is a material that is unlikely to cause deterioration in curability due to addition.

The particle size of the silica powder to be added is generally 0.01 μm or more and 10 μm
Hereinafter, the diameter is preferably 0.1 μm or more and 5 μm or less.

Furthermore, if the amount of silica powder added is too large, the curability of the resin will deteriorate, and if the amount is too small, a sufficient addition effect will not be obtained. Generally, it is desirable to add as much amount as possible within the range where the resin is cured. The maximum amount of addition necessarily depends on the thickness of the tape coating, but the maximum amount of addition can be determined by measuring the thickness of the cured film described above. For example, when the amount of irradiation light is IJ/cm2, From Figure 3, the maximum addition amount when the film thickness is 1 mm is determined to be 10% by weight. Examples will be described below.

〔Example〕

Comparative Example 1 On the outer periphery of an optical transmission glass fiber with a diameter of 125 μmφ,
Four coated optical fibers each having a diameter of 200 μmφ coated with a urethane acrylate UV curable resin having a Young's modulus of 0.2 Kg/mm2 and a diameter of 250 μmφ coated with a urethane acrylate UV curable resin having a Young's modulus of 40 Kg/mm2 were placed adjacent to each other. - Young's modulus 7
A 100 Qm long four-core optical fiber tape coated with urethane acrylate ultraviolet curable resin of 0 kg/mm'' and integrated as shown in Figure 2 was fabricated.The dimensions were 0.38 mm thick. The width is 1.05 mm.

The initial transmission characteristics of the optical fiber ribbon of Comparative Example 1 are that the transmission loss is 0°21 dB/Km at a wavelength of 1.55 μm.
Met.

After aging this optical fiber ribbon for 200 hours at a temperature of 80°C and 95% RH, the transmission characteristics were measured. 1. The transmission loss was 0.26 at a wavelength of 1.55 μm.
dB/Km, indicating an increase in loss of 0.05 dB/Km.

Further, using the urethane acrylate ultraviolet curable resin with a Young's modulus of 70 Kg/mm2 used for the tape coating of the optical fiber ribbon of Comparative Example 1, a strip-shaped sheet with a width of 25 ROM and a length of 100 mm was prepared, and the same procedure was carried out. 80°C
After being left under humid heat at 195% RH for 200 hours, the shrinkage rate in the longitudinal direction of the sheet was measured, and the shrinkage rate was 1.5.
%Met.

Example 1: An optical fiber tape core was produced in the same manner as in Comparative Example 1, except that 5% by weight of silica powder with a particle diameter of 1 μmφ was added to the urethane acrylate ultraviolet curable resin having a Young's modulus of 70 Kg/mm 2 for tape coating.

FIG. 1 shows the cross-sectional structure of the optical fiber ribbon 10 produced. 4 is glass fiber, 5 is optical fiber coating, 6
7 indicates tape coating and 7 indicates silica powder.

The initial transmission characteristics of the optical fiber tape of this Example 1 are at a wavelength of 1.55 μm and a transmission loss of 021 dB/Km.
Met.

The optical fiber ribbon of Example 1 was heated at 80°C and 95%
When the transmission characteristics were measured after being aged under RH moist heat for 200 hours, the transmission loss was 0.0 at a wavelength of 1°55 μm. 021 dB/Km, and no increase in loss was observed compared to the initial state.

In addition, the urethane acrylate-based ultraviolet curable resin with a Young's modulus of 70 and K g/mm 2 to which 5% by weight of silica powder with a particle diameter of 1 μm, which was used for the tape coating of the optical fiber ribbon of Example 1, was used. width 25m
m, a strip-shaped sheet with a length of 100 mm was prepared, and similarly 8
After being left under heat at 0°C and 95% RH for 200 hours, the shrinkage rate in the longitudinal direction of the sheet was measured, and the shrinkage rate was 0.
．． 1/7.5 of Comparative Example 1 without adding silica powder at 2%
It was extremely small.

Comparative Example 2: For further comparison, Young's modulus of 70 was used for tape coating.
Same as Comparative Example 1 except that 5% by weight of titanium oxide powder was added to the urethane acrylate-based ultraviolet curable resin of "Kg/mm", the relationship between the amount added and the cured film thickness is shown in Figure 3 for comparison with silica powder. When an attempt was made to fabricate an optical fiber ribbon, as can be seen from FIG. 3, the tape coating could not form a sufficient cured film, and the optical fiber ribbon could not be fabricated.

〔Effect of the invention〕

As explained above, the optical fiber ribbon of the present invention is
Since the tape coating is made of ultraviolet curable resin containing fine silica powder, shrinkage strain on the optical fiber due to shrinkage of the tape coating material is suppressed, and changes in transmission loss over time are suppressed. It is effective when applied to optical fiber ribbons for long-distance communications because it has little occurrence.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of an optical fiber ribbon embodiment of the present invention, Figure 2 is a cross-sectional view of a conventional optical fiber tape example, and Figure 3 shows the relationship between the amount of silica powder added and the cured film thickness. FIG. 1.4... Glass fiber, 2.5... Optical fiber coating, 3.6... Tape coating, 7... Silica powder,
10.20... Optical fiber tape coated wire Patent applicant Sumitomo Electric Industries Co., Ltd. Agent Patent attorney Tamamushi Kugobe Gen. Optical fiber tape coated wire Cross-sectional diagram of an embodiment of the optical fiber tape coated wire of the present invention Section 1
Figure 20, Cross-sectional view of an example of a conventional optical fiber tape core Figure 2

Claims (1)

[Claims] A tape-shaped optical fiber tape core in which a tape coating is applied all at once to the outer periphery of an assembly in which a plurality of optical fibers or optical fiber strands each having a protective coating are arranged in a row adjacent to each other. An optical fiber tape core wire, wherein the tape coating applied to the outer periphery of the aggregate is made of an ultraviolet curable resin containing fine silica powder.