JPH07103363B2 - Waterstop tape for optical fiber cable - Google Patents

Description

TECHNICAL FIELD The present invention relates to a water blocking tape for an optical fiber cable.

[Conventional technology]

Water-stop tapes are used for various purposes such as stopping water in communication cables. In recent years, optical fibers have come to be used for communication, and they are also attracting attention as water-stopping optical fiber cables. Generally, in optical fiber cables, most of the cable failures are due to water ingress into the cables, which causes bad phenomena such as deterioration of optical fiber strength and deterioration of transmission characteristics due to freezing.
For this reason, it has been practiced to dispose a water blocking tape provided with a water absorbing and swelling substance together with the optical fiber in the optical fiber cable. Examples of the water blocking tape include, for example, those having a water absorbing layer made of pulp fibers or the like containing powder of a water absorbing and swelling substance of a polyelectrolyte crosslinked polyelectrolyte or the like on the front and back surfaces of a plastic film or the like. Is mentioned. Since this water-stop tape has excellent water-absorption swelling property of the polyacrylate cross-linked product, it blocks the inundation point by swelling by contact with the water invading the cable during the infiltration in the optical fiber cable, which is excellent. It exerts a water blocking effect.

[Problems to be Solved by the Invention]

However, the water blocking tape has a drawback that it sticks to each other due to moisture absorption during storage. That is, the water blocking tape is wound around the outer circumference of the bobbin and stored, but since it absorbs moisture and adheres to each other during the rainy season, etc., it is pulled out from the bobbin and combined with the optical fiber into the optical fiber cable. When they are continuously inserted, inconveniences such as cutting due to mutual adhesion on the bobbin occur, and there is a problem in workability. Further, when the optical fiber cable is laid, a phenomenon occurs in which the optical fiber itself moves on the water blocking tape due to bending stress applied to the optical fiber cable. In this case, the tackiness of the surface of the water blocking tape due to the water blocking agent hinders the movement of the optical fiber, so that the optical fiber is distorted, which causes a problem that the transmission loss of light increases. There is.

The present invention has been made in view of the above circumstances, and does not cause moisture to stick to each other during storage and to prevent mutual adhesion of the optical fiber, and also to prevent the optical fiber from being distorted by suppressing bending of the optical fiber. Its purpose is to provide a waterproof tape for fiber cables.

[Means for Solving the Problems]

In order to achieve the above object, the water stopping tape for an optical fiber cable of the present invention is a water-absorbing material in which an organic water-swelling swelling substance is fixed to at least one surface of a film-like flexible substrate by a binder made of an organic polymer substance. A swelling substance layer is formed, and a hydrophobic organic filler having a particle diameter of 50 μm or less made of organic polymer substance powder is dispersedly contained in the water absorption swelling substance layer.

[Action]

The optical fiber cable water-stop tape of the present invention contains an organic filler composed of an organic polymer powder in a water-swelling substance layer in a dispersed manner, so that when the optical fiber cable is laid, an external force is applied to the cable, When trying to move the optical fiber, the optical fiber can move smoothly on the water blocking tape. Therefore, the increase in the transmission loss of the optical fiber caused by the inhibition of the movement of the optical fiber does not occur. In addition, the presence of the organic filler prevents the water-stop tapes from sticking to each other in a high humidity atmosphere such as the rainy season when the water-stop tapes are stored. Moreover, the water blocking tape for an optical fiber cable of the present invention is well compatible with each other because the water-swelling and swelling substance layer in which the organic filler is dispersed and contained is composed of the same organic material as the organic filler. The elimination of the organic filler does not occur.
Also, the binder that fixes the organic water-absorption swelling substance to the film is also composed of the same organic polymer material as the organic water-absorption swelling substance, so that they are well compatible with each other,
Peeling does not occur when the tape itself is bent.

Next, the present invention will be described in detail.

The waterproof tape for optical fiber cable of the present invention comprises a film-like flexible base material, an organic water-absorption / swelling substance, a binder made of an organic polymer substance, and an organic filler made of an organic polymer substance powder. To be done.

Examples of the flexible film base include plastic films such as polyethylene terephthalate film, polyethylene film and vinyl chloride resin film.
However, metal foil such as aluminum foil may be used as long as it has flexibility. In particular, the use of polyethylene terephthalate film gives good results.

Examples of the organic water-swelling substance include starch, a hydrolyzate of an acrylonitrile graft polymer, a neutralized product of a starch-acrylonitrile acid graft polymer, a hydrolyzate of a vinyl acetate-acrylic acid ester copolymer, or a cross-linked product thereof. Examples thereof include a hydrolyzate of an acrylamide copolymer, a crosslinked product thereof, a polyacrylate crosslinked product, and an isobutylene-maleic anhydride copolymer crosslinked product. These may be used alone or in combination. In particular, the crosslinked polyacrylate has excellent swelling performance and is widely used for waterproofing applications. Such a water-swelling substance is usually used in powder form. Since the water-absorption swelling substance itself does not have adhesiveness to the film-like flexible substrate, it is hardened with a binder to form an organic water-absorption swelling substance layer. At this time, the use ratio of the water-swelling swelling substance and the binder is preferably set so that the water-swelling swelling substance is 100 to 500 parts with respect to 100 parts by weight of the binder (hereinafter abbreviated as “part”). Bring Then, in order to reduce the surface friction resistance of the water-swelling substance layer,
It is preferable to use it in the form of powder particles of 50 μm or less. By doing so, for example, the optical fiber 4
Even if the optical fiber cable is subjected to mechanical and thermal external force, the optical fiber and the waterproof tape are arranged in a structure in which the tape core wire of the structure in which the books are arranged in one horizontal row and the waterproof tape are arranged side by side in the cable. The force applied to the optical fiber is reduced at the rubbing portion, and problems such as transmission loss are less likely to occur.

The binder used for fixing the organic water-absorption / swelling material layer is a binder made of an organic polymer material. As this binder, in addition to natural rubber, various butanediene rubber, isoprene rubber, butyl rubber, butadiene-styrene rubber, butadiene-acrylonitrile rubber, chloroprene rubber, ethylene-propylene-diene rubber, allyl rubber, chlorosulfonated polyethylene rubber, etc. I can give you rubber. These may be used alone or in combination. Further, synthetic resin is also used. Examples of the synthetic resin include ethylene-vinyl acetate copolymer, ethylene-propylene copolymer, acrylonitrile-butadiene copolymer, styrene-butadiene copolymer, polyester, polyamide resin, acrylic resin, styrene resin and the like. It should be noted that even a hard resin that is softened by using an appropriate plasticizer can be used. These resins may be used alone or in combination. In addition, one or more of the above rubbers may be used in combination with one or more of the above resins. In addition, since the crosslinked polyethylene oxide itself has water-swelling property, it can be used as a binder.

The filler dispersedly contained in the water-swelling substance layer is a hydrophobic organic filler made of organic polymer substance powder and having a particle size of 50 μm or less. As the organic filler, a hydrophobic one is used. Specific examples include powders of polyolefin such as polyethylene and polypropylene, and powders of fluorides of these polyolefins. Further, fluorine resin, powder, and silicon resin powder are also suitable. This type of filler has a particle size of 50 μm or less, and most preferably a particle size of about 5 to 20 μm. From the viewpoint of the effect, it is preferable to set the amount of the filler to be 5 to 100 parts with respect to 100 parts of the binder.

The water blocking tape for optical fiber cable of the present invention can be manufactured as follows using each of the above raw materials. That is, the organic water-absorption swelling substance, the binder, and the organic filler are mixed by powder mixing or the like, and this is dissolved and dispersed in an organic solvent, and this solution is formed into a film-like flexible film such as polyethylene terephthalate film. It can be manufactured by directly coating one or both surfaces of the substrate to form a water-swelling substance layer. The water-stop tape thus obtained is shown in FIG. In the figure, 1 is a film-like flexible substrate, 2 is a water-swelling substance layer, and 2a
Is an organic filler dispersedly contained in the water-swelling substance layer.

The water blocking tape thus obtained is used for an optical fiber cable. Thus, when used for an optical fiber cable, a flexible substrate 1 for film shown in FIG. 1 having a thickness of about 100 μm is used, and the thickness of the water-swelling / swelling substance layer 2 provided therein is set to about 50 μm. Is desirable in terms of effectiveness.

The water-stop tape thus obtained contains the organic filler 2a dispersed in the water-swelling and swelling substance layer 2, so that when the water-swelling substance layer 2 is wound around the bobbin etc. It does not happen that they stick to each other. Therefore, the workability is good.

Next, examples will be described together with comparative examples.

[Examples 1 to 4 and Comparative Example] As the water-swelling substance, the materials shown in Table 1 below were used, and the materials shown in Table 1 below were used as the binder, and both materials were mixed at the ratios shown in the same table. And was dissolved in a hydrocarbon-based organic solvent. Next, this was applied onto both surfaces of a polyethylene terephthalate film (thickness: about 100 μm) and dried to form a water-absorption / swelling substance layer having a thickness of about 50 μm.

The water supply ratio of the water-swelling substance layer of the water-stopping tape thus obtained was determined and shown in Table 1 below, and the coefficient of static friction and the water-stopping tape of the water-absorbing swelling substance layer with the optical fiber tape core resin were also shown. The mutual adhesive strength was investigated and shown in Table 1 below.

Further, the moisture absorption rate of the water-swelling substance layer in the water-stop tape obtained as described above, the relative humidity of the water-stop tape 5
It was put in an atmosphere of 0, 60, 70, 80, 90 RH% for 24 hours respectively and examined, and the moisture absorption rate under that atmosphere was examined, as shown in Fig. 2. In addition, the water absorption swelling material layer The static friction coefficient was investigated and shown in FIG. In these figures, the curve A shows the example 1, the curve B shows the example 2, the curve C shows the example 3, and the curve D shows the comparative example.

According to the above Table 1, FIG. 2 and FIG. 3, the examples have the same water absorption capacity and moisture absorption rate as compared with the comparative examples, but the adhesive strength and the friction coefficient in the high humidity atmosphere are compared. It is much lower than the example, and the movement of the optical fiber is smoothed based on the external force generated when laying the optical fiber cable, and there is almost no mutual adhesion even in a high humidity atmosphere such as during the rainy season. I understand.

〔The invention's effect〕

As described above, the water blocking tape for an optical fiber cable according to the present invention includes the hydrophobic organic filler having a particle diameter of 50 μm or less, which is made of an organic polymer powder, dispersedly contained in the water swelling substance layer. The external force applied when laying the cable enables the optical fiber to move smoothly when sliding on the water blocking tape. Therefore, the increase in the transmission loss of the optical fiber caused by the inhibition of the movement of the optical fiber does not occur. In addition, the presence of the organic filler prevents the waterproof tape from sticking to each other in a high humidity atmosphere such as the rainy season when the waterproof tape is stored. Moreover, since the water blocking tape for optical fiber cable of the present invention is composed of the water-swelling swelling substance, the binder, and the filler as organic materials, they are well compatible with each other, and therefore, the removal of the filler is not likely to occur. Delamination does not occur.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention, FIG. 2 is a relative humidity-moisture absorption characteristic curve diagram, FIG. 3 is a relative humidity-static friction coefficient characteristic curve diagram, FIG. 4 is a static friction coefficient measurement explanatory diagram, 5 (a) and 5 (b) are explanatory views for measuring the adhesive force. 1 ... Film-like flexible substrate, 2 ... Water-swelling substance layer, 2a
……filler

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yukio Sakuraba 3600 Amagatsu, Kita Sotoyama, Komaki City, Aichi Prefecture, Tokai Rubber Industry Co., Ltd. (72) Masanari Umeda, Komaki City, Aichi Pref. 3600 Tokai Rubber Industry Co., Ltd.

Claims (1)

[Claims] 1. At least one surface of a film-shaped flexible substrate,
An organic water-swelling swelling substance is formed by fixing a water-swelling swelling substance layer with a binder made of an organic polymer substance, and the particle diameter of the organic polymer substance powder is 50
A water blocking tape for optical fiber cable, wherein a hydrophobic organic filler having a particle size of not more than μm is dispersedly contained.