JPH0478962B2 - - Google Patents

Description

Detailed Description of the Invention Technical Field The present invention provides a water shield with improved water running prevention properties and flexibility, which is obtained by surrounding a plurality of optical fibers with a water blocking layer through a special water running prevention material. This invention relates to shaped optical fiber cables. 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. DISCLOSURE OF THE INVENTION In view of the above, some of the inventors of the present application have previously proposed the use of grease as a water running prevention material.
Grease generally has extremely low temperature dependence in its softness, so for example, the consistency of grease at room temperature is 220.
~475 grease is sufficiently soft and can be injected into optical fiber cables at room temperature without adding a heat softening process, and does not have excessive fluidity, which causes problems within optical fiber cables. No such flow occurs. Incidentally, in recent years, due to the increasing demand for high-quality optical fiber cables, there has been an increasing demand for producing them at as high a speed as possible. Through subsequent research, the present inventors discovered that some greases could meet the above requirements, and completed the present invention. That is, the present invention has a kinematic viscosity of 2 at 40°C.
~100 parts by weight of an organic liquid of ~1000 cSt and a carbon number of ~4
Surround multiple optical fibers with a water-shielding layer through a grease consisting of 2 to 15 parts by weight of lithium-based or aluminum-based metal soap of 40% organic acid and having a consistency of 220 to 475 at 25°C. The present invention provides a water-shielded optical fiber cable. The above-mentioned grease used in the present invention is characterized by a lower apparent viscosity than other greases even if the mixing consistency is the same. Therefore, the pressure during injection and filling into the optical fiber cable is reduced, and the degree of microbending in the optical fiber is reduced, making it possible to produce high-quality optical fiber cables, or by reducing the force applied to the optical fiber at the same level. In this case, there are remarkable effects such as the ability to further increase the pressure when injecting and filling an optical fiber cable, thereby increasing the production speed of the cable. 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, the water running prevention material has a kinematic viscosity of 2 to 1000 cSt at 40°C, preferably 5 to 1000 cSt.
100 parts by weight of an organic liquid of 500 cSt and a carbon number of 4 to 40
2 to 15 parts by weight, preferably 3 to 10 parts by weight of a lithium-based or aluminum-based metal soap of an organic acid, measured based on JIS K 2220-5.3.
A grease having a working consistency at 25° C. in the range of 220 to 475 is used. If the kinematic viscosity of the organic liquid at 40°C is less than 2 cSt, or if the ratio of metal soap to 100 parts by weight of the organic liquid is less than 2 parts by weight, the resulting grease will have excessive fluidity and will be unsuitable for use in the cable. Become something. On the other hand, if the kinematic viscosity exceeds 1000 cSt and the proportion of the metal soap exceeds 15 parts by weight, the resulting grease will have insufficient fluidity and poor filling properties, which is not preferred. On the other hand, even if the grease obtained under the above conditions has a mixing consistency of less than 220, it will have poor fluidity during filling, and on the other hand, if it exceeds 475, the fluidity will be excessive and the cable will not run vertically or at an angle. When installed in the cable, it may flow down inside the cable, create water head pressure inside the lower part of the cable that can cause sheath damage, or create air gaps in the upper part of the cable that can cause problems in preventing water running. I don't like it. The organic liquid used in the present invention includes:
For example, transformer oil, spindle oil, cable oil, etc. whose kinematic viscosity at 40℃ is in the range of 2 to 1000 cSt.
Insulating oil, petroleum oil such as machine oil, rosin oil,
Natural oils such as castor oil, olive oil, and whale oil; synthetic oils such as polybutenes, alpha-olefin oligomers, chlorinated paraffins, polyalkylene glycols, and esters; and the like. In addition, examples of metal soaps include lithium-based or aluminum-based metal soaps such as lithium soap, lithium complex soap, aluminum soap, and aluminum complex soap made of organic acids with carbon numbers of 4 to 40. , is selectively used in the present invention because compared to other soaps, it provides a grease with a lower apparent viscosity even though the mixing consistency is the same. Examples of the organic acids include linear or branched saturated or unsaturated fatty acids, aromatic carboxylic acids, etc., which have grease-forming ability under the above conditions, and typical examples include butyric acid, valeric acid,
Capric acid, palmitic acid, stearic acid, oleic acid, linoleic acid, behenic acid, cerotic acid,
Examples include melisic acid, benzoic acid, caprylic acid, myristic acid, palmitic acid, lauric acid, linolenic acid, montanic acid, 12-hydroxystearic acid, sebacic acid, and azelaic acid. The anti-water running agent of the present invention may consist of the above-mentioned grease alone, or may consist of the above-mentioned grease and, for example, the above-mentioned petroleum-based hydrocarbon oil, olefin polymerized oil such as polybutene, polyalkylene glycol oil, or chlorinated paraffin. halogenated hydrocarbon oils, such as
The grease may be a mixture of a liquid rubber such as liquid chloroprene rubber, liquid butadiene rubber, or liquid nitrile rubber, or a polymer compound such as silicone oil. Advantages of the Invention In the present invention, a grease having appropriate mixing consistency and low apparent viscosity is selected and used as the running waterproofing material. Therefore, for the reasons mentioned above, the optical fiber cable of the present invention maintains high quality and
It has the remarkable effect of enabling high-speed production. Furthermore, since the grease has an appropriate mixing consistency, the cable of the present invention does not cause any problem-prone grease flow inside the cable. Examples, Comparative Examples Reference Example 1 12 parts by weight of rapeseed hydrogenated fatty acid and castor hydrogenated fatty acid
36 parts by weight of α− with a kinematic viscosity of 86.4 cSt at 40°C
100 parts by weight of olefin oligomer was added and dissolved by heating to 90°C, and 16.5 parts by weight of lithium hydroxide (monohydrate) was dissolved by heating in 70 parts by weight of water. After converting to 150
℃ to remove moisture, then add 900 parts by weight of the α-olefin oligomer oil and stir.
After heating to 220°C and slowly cooling with stirring, 4,4'-thiobis(3-
Add 10 parts by weight of methyl-6-tert-butyl-phenol) and mill to obtain a mixing consistency (25℃, JIS
K2220−5.3 and below) 436 lithium soap grease (apparent viscosity: 40℃, shear rate 10 _s-1 , JIS
K2220−5.15 (same below): 65 poise) was obtained. Reference Examples 2 to 7 Greases having the composition and physical properties shown in Table 1 were prepared according to Reference Example 1.

【table】

[Table] Example 1 A GI type optical fiber with a core diameter of 50 μm and a cladding diameter of 125 μm is coated with a nylon jacket and has a diameter of 0.9
Six optical fibers with a diameter of 1.0 mm are connected to a piano wire with a diameter of 1.0 mm, and each optical fiber is connected at a pitch of 10 cm.
Thickness of 50 μm is obtained by winding at a circular rate.
A 6-optical fiber unit (outer diameter 3.0 mm) formed by winding a stretched polyethylene film tape with a width of 2.5 mm at a tape spacing of 1.0 cm.
The 8 pieces were wound around a tension member made of piano wire with a diameter of 5.0 mm so that each unit made one turn at a pitch of 40 cm, and the aggregate with an outer diameter of 11 mm was obtained by forming a large number of small holes with a diameter of 5 mm. The sample was passed through a tapered cylindrical body (at room temperature). Water running prevention material is extruded from the small holes of this cylindrical body at 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. A 16 mm diameter piece covered with the water running prevention material thus obtained was laminated with a modified polyolefin adhesive on one side at a thickness of 50 μm.Thickness: 250 μm, Width: 57 mm
A water-shielding optical fiber cable with an outer diameter of 23 mm is created by vertically attaching aluminum laminate tape with a diameter of 23 mm to form a water-shielding layer, and then introducing this into an extrusion molding machine to form a polyethylene sheath layer with a thickness of 3 mm.
Obtained continuously at a speed of 15 m/min. As the water running inhibitor, the one in Reference Example 1 was used. The resulting cable was one in which all the gaps between the optical fiber units and between the optical fibers within the units were filled with grease. Furthermore, the performance of the cable was excellent as shown in Table 2. 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, regarding cable flexibility, bending radius
A mandrel winding method was applied in which repeated bending was performed 10 times at ±180 degrees along a 200 mm mandrel, and an increase in optical loss of 0.1 dB/Km or less was considered good, and anything else was judged as poor. After that, all the optical fibers in the cable were connected in series and the ends were fixed with epoxy resin, and then 0.85 μm light was constantly transmitted through the cable, and the increase in optical loss was measured from the change in the received light level. Example 2 Another layer 8 on top of the optical fiber unit layer
A cable was obtained in the same manner as in Example 1, except that an optical fiber unit layer consisting of book units wound at a pitch of 20 cm was provided. The filling properties of this cable were good, and its performance is shown in Table 2. Examples 3 to 5 Cables were obtained in the same manner as in Example 1 except that the type of water running prevention material was changed. The results are shown in Table 2. Comparative Example 1 #5B manufactured by Utsutco, USA was used as the anti-water running material, and as it is solid at room temperature, it was heated to 105°C, melted, filled, and left to cool at room temperature, but in the same manner as in Example 1. Got cable. The filling properties and performance of this product are shown in Table 2. Comparative Examples 2 and 3 Cables were obtained in the same manner as in Example 1, except that the materials of Reference Examples 6 and 7 were used as water running prevention materials. The results are shown in Table 2. In addition, a defect in the evaluation of filling property means that an unfilled portion as voids was observed in the filled portion of the water running prevention material between the optical fiber units.

【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)

[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 has a kinematic viscosity of 2 to 2 at 40°C.
100 parts by weight of an organic liquid of 100 cSt and a carbon number of 4 to 40
2 to 15 parts by weight of a lithium-based or aluminum-based metal soap of an organic acid, and having a mixing consistency at 25° C. in the range of 220 to 475.