JPH01245207A - Waterproof type optical fiber cable - Google Patents

Abstract

PURPOSE:To form the cable having high strength and sufficient water absorption characteristic by using a water absorptive tape formed by sticking woven or non-woven fabrics coated on or impregnated with a water absorptive swellable material as a tensile tape. CONSTITUTION:The water absorptive tape 3 is formed by providing the woven or non-woven fabrics 5 coated on or impregnated with the water absorptive swellable material on one or both faces of the tensile tape 4. For example, this tape is formed by using a 25mum PET film as the tensile tape 4 of the water absorptive tape 3, sticking the non-woven fabrics produced by a span bonding method from a polyester resin having 20g/m<2> unit weight to both faces of the film and coating a soln. prepd. by dissolving powder of a polyacrylic acid system having the capacity of 200 times the saturation water absorption magnification of water at 2:1 ratio in a resin for a binder on this non-woven fabric. The mechanical strength is thereby improved and the cable having the excellent water absorptivity is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a waterproof optical fiber cable.

(Prior Art) Waterproof optical fiber cables are relatively new and are not yet widely used.

Conventional waterproof optical fiber cables were filled with petroleum-based admixtures to prevent water from entering the voids inside the cables, but recently, water absorption is 1Ilfr! A method has been considered to prevent water running by filling the material with a 4-character material. In this case, in order to prevent water from running between the plurality of optical fiber tapes C stored in the grooves B of the grooved spacer A as shown in FIG. A method has been considered in which a tape D is inserted.

(Problems with the prior art) The tape D has a width of about 1 to 2 mm, which is very thin.
Strong strength and sufficient water absorption properties are required, but a tape that can satisfy these requirements has not yet been developed.

(Means for solving the problem) The waterproof optical fiber cable of the present invention is as shown in FIG.
In an optical fiber cable formed by storing an optical fiber tape core 2 in which a plurality of optical fiber cores are tape-shaped and a water-absorbing tape 3 in a storage groove 1 of a grooved spacer 7, the water-absorbing tape 3 This is characterized in that a woven or nonwoven fabric 5 coated or impregnated with a water-absorbing and swelling substance is provided on one or both sides of the tensile strength tape 4.

(Embodiment) FIG. 1 is an explanatory diagram showing an embodiment of the optical fiber cable of the present invention. In Figure 1, 6 is the center antigravity body, 7 is the grooved spacer, ■ is the storage groove for the grooved spacer, 2 is the storage groove l
3 is a water-absorbing tape, 8 is a pressing layer, and 9 is a sheath.

The water-absorbing tape 3 may be laminated between the optical fiber tape cores 2 as shown in FIG. You may also place it on the other side.

The water absorbent tape 3 has a width of about 1 to 2 mm so that it can be stored in the storage groove 1, and a thickness of about 1 to 2 mm so that a large number of optical fiber tape cores 2 can be stored in the storage groove 1. It is desirable to make it as thin as possible.

The tensile strength tape 4 constituting the water absorbent tape 3 is desirably made of a material with high tensile strength, and examples of such materials include polyethylene terephthalate (hereinafter abbreviated as PET), nylon, and high-density PE.

It is desirable that the tensile strength tape 4 has a thickness of 0.1 mm or less, and for that purpose, the tensile strength is at least 1 kg/
mm2 is required. Films made of these materials have smooth surfaces, so it is impossible to coat them with many water-absorbing resins. Therefore, in the present invention, a tape made of non-woven fabric or woven fabric with a non-smooth surface is used, and the coating amount is twice to several times that of a smooth film. However, since this tape does not have sufficient tensile strength, it is used by laminating it to the tensile strength tape 4 for reinforcement.

The nonwoven fabric is polyester.

Any nylon type material can be used.

The water-absorbing and swelling substance may be impregnated into the non-woven fabric 5 instead of being applied thereto.

The water-absorbing tape 3 shown in FIG. 2 is a tensile tape 4 with a non-woven fabric 5 on both sides, and the water-absorbing tape 3 shown in FIG. 3 is a tensile-strength tape 4 with a non-woven fabric 5 on only one side.

As an example of the water-absorbent tape 3, 2 is used as the tensile strength tape 4.
A 5Bm PET film is used, and 20g/
A polyester resin with a unit weight of m2 is laminated with a nonwoven fabric produced by the spunpond method, and a polyacrylic acid powder with a saturated water absorption capacity of 200 times that of water is added to the nonwoven fabric as a binder resin. It was created by applying a solution melted at a ratio of 2:1. The amount of application in this case is converted to powder amount of 25g/m' and 50g/m'.
There were two types of m2. These are slit to a width of 1.5 mm, and the width is 1.6 mm and the depth is the tape thickness + 0.
A piece of wood was inserted into a 6 mm rectangular tube, water pressure was applied to the cross section of one end of the tube, and the length of water running inside the chip was observed.

(Comparative Example) The powder used in the above example was applied to a PET film having a thickness of 50 gm to prepare a water-absorbing tape 3 with a coating amount of 25 g/m. In this case, if the applied amount was more than this, the powder would fall off when the tape was slit, etc., and the above-mentioned applied amount was almost at its limit. The water running characteristics of this product were observed under the same conditions as in the above example. The results were as follows.

(Otori), Example 1 cloth! 25 g/m2) (7) Case:
Water running length 75 cm (2), In the case of the example (application amount 50 g/m2): Wood running length 30 cm (3), In the case of the comparative example: Water running length 120 cm''-2 Which of the two examples and comparative examples In this case, there were no problems in manufacturing the cable, but tensile strength tape 4
A water-absorbing tape made of non-woven fabric and slit to 1.5 mm had a low tensile strength, making it impossible to manufacture a cable.

(Effect of the invention) The optical fiber cable of the present invention has the following effects.

(i) A water-absorbing tape 3 in which a woven or non-woven fabric 5 coated with or impregnated with a water-absorbing swelling substance is attached to a tensile tape 4
is used, so compared to a tape in which the nonwoven fabric 5 is not bonded to the tensile strength tape 4, more water-absorbing powder can be applied and the water-absorbing property is excellent. Further, even if the amount of the water-absorbing and swelling substance applied is the same, the water running property is better than that of a tape in which the nonwoven fabric 5 is not bonded to the tensile strength tape 4.

(2) Since it is a combination of the tensile strength tape 4 and the woven fabric or non-woven fabric 5, the mechanical strength is improved and the cable has the necessary tension when manufacturing the cable.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an example of an optical fiber cable according to the present invention, FIGS. 2 and 3 are explanatory diagrams of different examples of water-absorbing tape used for the cable, and FIG. 4 is an explanatory diagram of the same water-absorbing tape. FIG. 5 is an explanatory diagram showing an example of a conventional optical fiber cable. l is a storage groove 2 is an optical fiber tape core 3 is a water-absorbing tape 4 is a tensile strength tape 5 is a woven fabric or non-woven fabric

Claims (1)

[Claims] In an optical fiber cable formed by storing an optical fiber ribbon 2 in which a plurality of optical fibers are tape-shaped and a water-absorbing tape 3 in a storage groove 1 of a grooved spacer, the water-absorbing tape 3 has a tensile strength. On one side or both sides of the tape 4,
Woven fabric or nonwoven fabric coated with or impregnated with a water-absorbing and swelling substance 5
A waterproof optical fiber cable characterized by being provided with.