JPS63170607A - Core of tape optical fiber cable - Google Patents

Abstract

PURPOSE:To enable easy stripping of optical fibers by the hand work and to improve the property of the optical fiber cable for collective surrounding and branching by constituting a collective protective coating layer comprising ultraviolet ray cured resin of a flexible inner layer and a rigid outer layer. CONSTITUTION:An optical fiber tape core cable 10 constituted of plural numbers of optical fibers 12 is produced by covering optical fibers with an ultraviolet ray cured resin and arranging the optical fibers parallely to each other, and a collective protective coating layer 14 comprising an ultraviolet ray cured resin applied to the plural optical fibers 12 collectively. The collective protective coating layer 14 comprises a flexible inner layer 14A and a rigid outer layer 14B which is formed in the outside of the inner layer 14A and having higher rigidity than the inner layer 14A. The inner layer 14A serves mainly to separate the optical fibers 12. On one hand, since the surface of the inner layer 14A is sticky, an outer layer 14B is formed to prevent the generation of abnormal tension in the stage of production. By this constitution, execution of collective connection and branching are facilitated, so the optical fiber is applicable to uses in wide field including wiring system.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to improvements in optical fiber ribbons used in public communications.

(Prior art) In general, optical fiber tape is a process in which optical fibers are coated with, for example, ultraviolet curable resin, and a plurality of optical fibers are lined up in parallel, and these optical fibers are coated all at once. It consists of a collective protective coating layer of ultraviolet curable resin. This type of optical fiber ribbon can be manufactured at high speed since a plurality of optical fiber ribbons are manufactured at once, and therefore can be provided at a low price, and has been put to practical use in feeder systems of optical subscriber lines. On the other hand, it has been difficult to use this type of optical fiber ribbon for wiring systems for various reasons. One reason for this is that, for example, there is a large loss when connecting multiple single-mode fibers at once, and another reason is that it is difficult to apply the free wiring method, which is a typical method for optical subscriber wiring. be. In particular, when introducing optical fiber ribbon into a wiring system, there is a problem that with conventional optical fiber tape, it is not possible to separate individual optical fibers when branching due to increased demand. there were. The reason for this is that the collective protective coating layer has a Young's modulus of 30 due to the requirement for wear resistance.
Kg/mm'' or more is common, and as a result, the collectively protected layer is too hard.

(Objective of the Invention) The object of the present invention is to provide an optical fiber tape core that facilitates bulk connection and branching, can be applied to a wide range of applications including wiring systems, is wear-resistant, and is easy to handle. It is about providing.

(Structure of the Invention) The optical fiber ribbon according to the present invention is coated on an optical fiber with W11f! A plurality of optical fiber strands arranged in parallel in a plane and a collective protective coating layer made of ultraviolet curable resin are applied to these plurality of optical fiber strands at once. However, this collective protective coating layer is characterized by being separated from the soft inner layer and the outer layer, which is provided outside the inner layer and is harder than the inner layer.

In this way, the hard outer layer provides wear resistance, and the soft inner layer allows the bulk protective coating to be easily peeled off manually, making it easy to separate the optical fibers and branch them. In addition to improved performance, the free wiring method can be applied, expanding the range of applications to include wiring systems.

(Example) An example of the present invention will be described in detail with reference to the drawings. Drawing 9 shows an optical fiber ribbon core 10 according to the present invention, and this optical fiber ribbon core 10 has an ultraviolet curing type for the optical fiber. Multiple optical fibers coated with resin and arranged in parallel 1
2 and a collective protective coating layer 14 of ultraviolet curable resin applied to these plurality of optical fiber strands 12 all at once. As shown in the drawing, this collective protective coating layer 14 is a soft layer. ) 14A and J of this! ! 14A and an outer layer 14B that is harder than the inner layer 14A. The optical fiber wire 12 is, for example, 2Kg/mm"
A material having the following drawing tension is used. soft inside
a14A is mainly used for the purpose of separating the optical fiber strands 12, and since the surface of this inner layer 14A is sticky, the outer layer 14A is used to prevent abnormal tension from occurring during manufacturing. 14
B is provided. These inner layer 14A and outer layer 14
B may be made of the same ultraviolet curing resin 9, for example, the same urethane resin.

The hard outer layer 14B is required to be as thin as possible in order to be easily torn when branching, and therefore preferably has a thickness of 10 to 20 #Lm.
If the outer layer 14B becomes more difficult to break, and if you try to break it by force, there is a risk that an unexpected force will be applied to the optical fiber and cause an increase in transmission loss.
If the thickness is less than μm, it becomes difficult to manufacture.

This is because variations in coating thickness occur. still.

This outer layer 114B is required to have better wear resistance than the inner layer 14A, and therefore its Young's modulus is 20
Kg/mm" or more is preferable.

The soft inner layer 14A has a Young's modulus of less than 5 g/m m'', especially when the Young's modulus at 20°C is E(20) and the Young's modulus at -40°C is E(-40). .

It is preferable that l≦E (-40)/E (20)≦3. In this way, J! 514A
has little change in characteristics (Young's modulus) due to temperature changes9
It was confirmed that there is almost no difference in workability during branching even at low temperatures and at room temperature.

In consideration of branchability, the optical fiber ribbon 10 is set to have an outer diameter of the optical fiber d, and the thickness of the inner layer 14A is set to t.

It is preferable to set 0.1≦t/d≦0.5.The reason is that if the thickness of the inner layer 14A is less than 0.1 d, the coating will be biased and the shape of the inner layer will not be formed. On the other hand, if it is 0.5d or more, the separability of each strand at the time of nine branches will deteriorate.

The present invention was applied to a 200-fiber cable and various characteristics were evaluated, and it was confirmed that the various characteristics were sufficiently practical and that the branching workability was good at an average of 30 seconds/tape.

(Effects of the Invention) According to the present invention, as described above, since the collective protective coating layer made of ultraviolet curable resin is composed of a soft inner layer and a hard outer layer, it is possible to easily separate optical fibers by hand. Since it can be peeled off, it improves the bulk continuity and branching properties, thus expanding its range of applications. In addition, the hard outer layer provides the core with wear resistance, and the soft inner layer provides the core with a buffering effect and the effect of absorbing stress in the longitudinal direction due to temperature changes. We can provide fiber ribbons. Furthermore, by forming the collective protective coating layer with an ultraviolet curable resin, changes in characteristics over time are reduced in various respects compared to those coated with a conventionally commonly used thermosetting resin. The reason for this is that this type of optical fiber ribbon is housed inside a sheath and made into a cable, so the influence of ultraviolet rays from the outside is blocked.
Because the effects of heat cannot be completely blocked, the hardness of thermosetting resins tends to change over time. Therefore, optical fibers coated with ultraviolet curable resins are better than optical fibers coated with thermosetting resins. This is because it is assumed that the transmission characteristics and branching properties are more stable over a long period of time than fibers.

[Brief explanation of the drawing]

The drawing is a sectional view of an optical fiber ribbon according to the present invention. 10----One optical fiber tape core, 12------
Optical fiber strand, 14 --- Collective protective coating layer, 14
A---inner layer, 14B---m-outer layer.

Claims (1)

[Scope of Claims] (1) A plurality of optical fibers provided with a coating layer and arranged in parallel in a plane, and ultraviolet rays applied all at once to the plurality of optical fibers. In an optical fiber tape core consisting of a bulk protective coating layer made of curable resin,
The optical fiber tape core is characterized in that the collective protective coating layer comprises a soft inner layer and an outer layer provided outside the inner layer and harder than the inner layer. (2) The optical fiber ribbon according to claim 1, wherein the outer layer has a thickness of 10 to 20 μm. (3) The optical fiber ribbon according to claim 1 or 2, wherein the inner layer has a Young's modulus of 5 kg/mm^2 or less. (4) When the Young's modulus of the inner layer at 20°C is E(20) and the Young's modulus at -40°C is E(-40), 1≦E(-40)/E(20)≦3 An optical fiber ribbon according to any one of claims 1 to 3. (5) Claims 1 to 4 of the present invention satisfy 0.1≦t/d≦0.5, where d is the outer diameter of the optical fiber and d is the thickness of the inner layer. The optical fiber tape core described in any of the above.