JPH0478963B2 - - Google Patents

Description

Detailed Description of the Invention Technical Field The present invention relates to the maintenance of the anti-water running effect obtained by surrounding a plurality of optical fibers with a water-blocking layer via a water-running preventing material made of a special grease, and the maintenance of the water-running prevention effect of the cable. The present invention relates to a water-shielded optical fiber cable with improved long-term stability. BACKGROUND ART A water-shielding optical fiber cable is known in which a space formed between a large number of optical fibers and a water-shielding layer surrounding the optical fibers is filled with a water running prevention material. The purpose of interposing the anti-travel material is mainly to prevent water that has entered through the damaged part, such as a hole, from penetrating into the internal optical fiber section and causing negative effects when a damaged part such as a hole is formed in the water-blocking layer. It's about doing. Conventionally, materials that are solid at room temperature have been known as water running prevention materials. That is, a type is known in which the fiber is heated and melted at the time of filling and injected into the gap between the optical fiber and the water-shielding layer. However, since the above-mentioned type is cooled after filling and solidifies at room temperature, it has the disadvantage that cracks occur due to volumetric shrinkage during the cooling process, reducing its water running prevention performance. This has the serious disadvantage of causing microbends in the optical fiber. In addition, it is difficult to remove from the cable after solidification, which causes various inconveniences in terminal processing such as connecting optical fiber cables that require a high degree of precision, and poor flexibility during work. It also had drawbacks such as poor handling. In view of the above, some of the inventors of the present invention have previously proposed the use of grease as a water running prevention material. Grease generally has extremely low temperature dependence in its softness, so it is soft even at room temperature and can be injected into optical fiber cables at room temperature without going through the heat-softening process. Therefore, no problematic flow occurs within the optical fiber cable. However, the inventors' subsequent research revealed that when a cable piece filled with grease is held vertically for a long period of time with both ends open, oil separated from the grease drips from the lower end of the cable. This phenomenon occurs because the grease first separates into oil and thickener, and then air, which normally exists in large amounts in the cable, adheres to the solid thickener, reducing the apparent specific gravity of the thickener. It turned out that this was because separated oil collected at the bottom of the cable and flowed down from the lower end of the cable. DISCLOSURE OF THE INVENTION The present invention overcomes the above-mentioned drawbacks by using a special grease that is difficult to separate as a water running prevention material, and also improves the sustainability of the water running prevention effect. That is, the present invention provides (a) K, Na, Li, Ca of organic acids having 1 to 7 carbon atoms and organic acids having 8 to 36 carbon atoms.
or a metal selected from Ba complex soap, (b) Al complex soap of benzoic acid and an organic acid having 8 to 36 carbon atoms, and (c) a metal salt of an organic acid having 8 to 36 carbon atoms. Consisting of 4 to 40 parts by weight of soap and 100 parts by weight of a hydrocarbon oil with an aniline point of 50 to 110°C and a kinematic viscosity of 8 to 600 cst at 40°C, and a mixing consistency at 25°C of 85 to 400. The present invention provides a water-shielded optical fiber cable in which a plurality of optical fibers are surrounded by a water-shielding layer via a water running prevention material made of grease. The cable of the present invention has a structure as shown in the attached drawings, for example. In this method, six optical fibers 12 are assembled around a tension member 11 made of organic polymer fibers such as Kepler or FRP, or metal wires, and a wrapped tape 13 is wrapped around the tension member 11 in an appropriate manner. The 8 units of the 6-core optical fiber unit 1 formed by coarsely winding the tapes at intervals are made of, for example, rubber, plastic, or rods made of fiber reinforced materials thereof, metal wires, organic polymer fibers, etc. This is assembled around the tension member 2, and the water running prevention material 5 is press-fitted into the internal space of the resulting assembly, and a slight amount of water running prevention material layer is also formed on the outer periphery of the assembly. is surrounded by a water-blocking layer 3 formed by longitudinally applying a laminated tape made of metal such as aluminum or lead, and on top of that is a layer of polyethylene or polyvinyl chloride bonded to an adhesive layer such as the laminated tape. It is manufactured by forming a protective sheath layer 4 made of a sheath material such as by extrusion molding. Although it is not essential, it is desirable that the anti-water running material 5 is also densely filled inside the optical fiber unit 1. The coarse winding of the tape 13 in the optical fiber unit described above is intended to achieve this purpose. That is, the water running prevention material is press-fitted between the tapes 13. In the present invention, a grease that is difficult to separate is used as the water running prevention material. That is, (a) a complex soap containing K, Na, Li, Ca or Ba of an organic acid having 1 to 7 carbon atoms and an organic acid having 8 to 36 carbon atoms, and (b) benzoic acid and an organic acid having 8 to 36 carbon atoms. ~36 organic acids Al
Complex soap and (c) 4 to 40 parts by weight of one or more metal soaps selected from metal salts of organic acids having 8 to 36 carbon atoms and an aniline point of 50 to 110.
A grease consisting of 100 parts by weight of a hydrocarbon oil having a kinematic viscosity of 8 to 600 cst. at 40° C., preferably 60 to 110° C., is used. If the ratio of metal soap to 100 parts by weight of hydrocarbon oil is less than 4 parts by weight, it will not be possible to obtain a grease that is difficult to separate.
If the amount exceeds 1 part by weight, the resulting grease will have poor fluidity, which is not preferable. Furthermore, if the aniline point and kinematic viscosity at 40° C. of the hydrocarbon oil are outside the above ranges, it will not be possible to obtain a grease that is difficult to separate. Examples of the organic acid having 1 to 7 carbon atoms in (a) above include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, benzoic acid, etc.
As the organic acid having 8 to 36 carbon atoms in ~(c),
For example, capric acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, montanic acid, melisic acid, oleic acid, linoleic acid, linolenic acid, tricosanoic acid, ricinol. acids, azelaic acid, sebacic acid, phthalic acid, toluic acid, phenyl acetic acid, cinnamic acid, palm fatty acid, tallow fatty acid, castor fatty acid, rapeseed fatty acid,
Examples of metals that form metal salts of wool fatty acids, fish oil fatty acids, whale oil fatty acids, and their hydrogenated fatty acids include Na, K, Li, Ba, Ca, and Al. Specific examples of the metal soap used in the present invention include benzoic acid/stearic acid-Al complex soap, acetic acid/behenic acid-Na complex soap, acetic acid/stearic acid-Ba complex soap, and acetic acid/stearic acid-Ba complex soap. Butyric acid/stearic acid-
Ca complex soap, sebacic acid, 12-hydroxystearic acid, caproic acid - Li complex soap, beef tallow hydrogenated fatty acid - Sodium soap, beef tallow hydrogenated fatty acid - Ba soap, castor hydrogenated fatty acid -
Ca soap, castor hydrogenated fatty acid/rapeseed hydrogenated fatty acid-Li soap, acetic acid/beef tallow fatty acid-K complex soap, acetic acid/palm hydrogenated fatty acid-Ca complex soap, butyric acid/palm fatty acid/rapeseed fatty acid-Na complex Soap, caproic acid/fish oil hydrogenated fatty acid-Na complex soap,
Benzoic acid/behenic acid-Al complex soap,
Examples include stearic acid-K soap and linoleic acid-Ba soap. The grease used as the water running prevention material in the present invention has a mixing consistency at 25° C. in the range of 85 to 400 based on JIS K2220-5.3.
If the mixing consistency is less than 85, it will be substantially similar to the conventional type, which requires heating to high temperature to increase fluidity during filling, and on the other hand,
If it exceeds 400, the fluidity becomes excessive, and if the cable is installed vertically or at an angle, it may flow down within the cable, or it may create a head pressure inside the lower part of the cable that can cause sheath damage. This is undesirable because it creates a void in the upper part of the cable that causes problems in preventing water running. Advantages of the Invention According to the present invention, since the water running prevention material made of grease that is difficult to separate is used, the water running prevention material has excellent stability, the water running prevention effect is maintained for a long period of time, and the grease separation is prevented. The resulting oil layer can be used without leaking from the end of the optical fiber cable and contaminating the end equipment. Furthermore, since the grease has an appropriate mixing consistency, it can be filled at a heating temperature of not room temperature or a relatively low temperature, and there is no or only slight volumetric shrinkage after filling. Therefore, no cracks occur in the water running prevention material layer made of the grease, and there are fewer micro-bends in the cable (optical fiber). As a result, the cable of the present invention not only has excellent optical transmission characteristics and water-blocking properties, but also can be easily removed when processing the end of the cable because it does not harden at room temperature.
Therefore, the terminal processing work can be carried out efficiently and precisely. Furthermore, since the cable has flow deformability under pressure, it is easy to bend and has excellent handling properties, and when the cable is bent, the water running prevention material interposed between the optical fibers (units) acts as a lubricant. It also has the effect of helping the smooth bending of individual optical fibers (units). Examples, Comparative Examples Reference Example 1 40 parts by weight of acetic acid and 100 parts by weight of rapeseed hydrogenated fatty acid were mixed into hydrocarbon oil with an aniline point of 80°C (ν ₄₀ : 138.6 cSt)
500 parts by weight and heated to 90°C and 36.7 parts by weight of sodium hydroxide dissolved in 100 parts by weight of water were mixed and saponified with stirring. After saponification was completed, the water was removed by heating to 150°C, and then 500 parts by weight of the hydrocarbon oil was added under stirring to give 200 parts by weight.
After heating to ℃, let it cool and add α- as an antioxidant.
Naphthylamine was added and milled to obtain acetic acid/rapeseed hardened fatty acid-Na complex stone grease. The mixing consistency of this grease (25℃,
JIS K2220−5.3 (hereinafter the same) was 296. Further, the degree of oil separation was 0.5% by weight at 100° C. for 2 days based on JIS K 2220-5.7. Reference Examples 2 to 20 Greases having the composition and physical properties shown in Table 1 were prepared according to Reference Example 1. In addition, reference examples 1 to 15
is the grease used in the present invention, and is the first grease used in the present invention.
As shown in the table, the degree of oil separation is low. On the other hand, Reference Examples 16 to 20 are greases of comparative examples and have a high oil separation degree because the aniline point of the hydrocarbon oil used is too high or the kinematic viscosity at 40°C is too low.

[Table] Example 1 Diameter of a GI type optical fiber with a core diameter of 500 μm and a cladding diameter of 125 μm with a nylon jacket
Six 0.9 mm optical fibers were wound around a 1.0 mm diameter piano wire as a core wire, with each optical fiber making one turn at a pitch of 10 cm, resulting in a thickness of 50 μm.
A 6-core optical fiber unit (outer diameter 3.0 mm) formed by wrapping a stretched polyethylene film tape with a width of 2.5 mm at a tape spacing of 1.0 cm.
A collection of 11 mm in outer diameter was obtained by continuously winding 8 pieces of wire around a 5 mm diameter piano wire tension member at a pitch of 40 cm so that each unit made one turn. It was passed through a tapered cylindrical body (at room temperature). Water running prevention material is pressed through the small holes of this cylindrical body with a pressure of 1.0 kg/cm ² .
As a result, the anti-water running material is press-fitted into the gaps between the units and between each optical fiber of the assembly passing through this. The thus obtained water running prevention material covers the outer periphery of a 16 mm diameter piece with a modified polyolefin adhesive laminated to a thickness of 50 μm on one side and a width of 250 μm.
A water-shielding layer is formed by longitudinally attaching 57mm aluminum laminate tape, and then this is introduced into an extrusion molding machine to form a 3mm-thick polyethylene sheath layer to create a water-shielding optical fiber cable with an outer diameter of 23mm.
Obtained continuously at a speed of 15 m/min. The water running prevention material used was that of Reference Example 1. In the resulting cable, all of the gaps between the optical fiber units and between the optical fibers were filled with grease. Also, the performance of the cable is second to none.
As shown in the table, it was excellent. Regarding the water shielding property of the cable, the length is 2m.
Strip off 25 mm of the sheath layer and vertical water shielding layer at approximately the center of the cable test piece.
A polyethylene pipe (diameter 30 mm) filled with water was installed at a height of 1 m, and the presence or absence of water leakage from both ends of the cable was investigated after 14 days. Furthermore, if there was no water leakage, the cable was dismantled and the distance of water intrusion was investigated. In addition, the long-term stability of the cable is REA standard PE-
It was evaluated according to 39 cable drip tests. Examples 2 to 11 Cables were obtained according to Example 1 with various types of anti-water run material. Its properties are shown in Table 2. Comparative Example 1 Example 1 except that #5B manufactured by U.S.-based Witt Co., Ltd., which is solid at room temperature, was used as a water running prevention material, and as it is solid at room temperature, it was heated and melted at 105°C, filled, and left to cool at room temperature.
I got the cable in the same way. The performance of this product is shown in Table 2. Comparative Example 2 A cable was obtained in the same manner as in Example 1, except that the easily separable grease of Reference Example 16 was used. The performance of this product is shown in Table 2.

【table】

【table】 [Brief explanation of the drawing]

The figure is a cross-sectional view showing a structural example of the water-shielded optical fiber cable of the present invention. 1: 6-core optical fiber unit, 2, 11: tension member, 3: water-blocking layer, 4: protective sheath layer,
5: Water running prevention material, 12: Optical fiber, 13: Pressure winding tape.

Claims (1)

[Scope of Claims] 1. In a water-shielding optical fiber cable formed by surrounding a plurality of optical fibers with a water-shielding layer through a water-running prevention material, the water-running prevention material is comprised of the following (a) to (c). ) 4 to 40 parts by weight of metal soap selected from ) and 50 to 50 parts of aniline point
The above-mentioned cable is characterized in that the grease is composed of 100 parts by weight of a hydrocarbon oil having a kinematic viscosity of 8 to 600 cst. at 110°C and 40°C, and has a mixing consistency at 25°C of 85 to 400 cst. (a) A complex soap containing K, Na, Li, Ca or Ba of an organic acid having 1 to 7 carbon atoms and an organic acid having 8 to 36 carbon atoms. (b) Al complex soap made of benzoic acid and an organic acid having 8 to 36 carbon atoms. (c) Metal salts of organic acids having 8 to 36 carbon atoms.