KR910004711B1 - Waterproof optical fiber cable - Google Patents

Abstract

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Description

Water resistant fiber optic cable

1 and 2 are cross-sectional views of embodiments of the present invention.

The present invention relates to a water resistant optical fiber cable having a filler, i.e., a moisture barrier material therein for preventing moisture from penetrating into the cable from the outside.

If the sheath of the fiber optic cable is locally ruptured, moisture naturally enters the cable and impairs the light transmission of the cable.

For optical fiber cables, a system has been proposed for initial detection of cable breakage and subsequent water penetration into the cable by monitoring the gas pressure charged in the cable to a high pressure. However, this proposed surveillance system is expensive and requires an excessively expensive cable system.

A method of providing a moisture barrier layer directly under the cable sheath and filling the inner space of the layer with a moisture barrier material in order to directly prevent moisture from entering the cable even in the event of a rupture in the cable sheath has been proposed. For example, JECE-JAPAN-NCR (The Institute of and Communication Engineers of Japan, National Convention Record) No. 1901 (pages 7 to 344), 1981 and JECE-JAPAN-NCR No. 366 (pages 2 to 102) .1810 (pages 7-252) and No. 1811 (pages 7-253), 1982. This method has the advantage of being economical because the above-described monitoring system is unnecessary.

Moisture barrier materials known for optical fibers are either solid or high viscosity liquids at room temperature. Such materials thus heat melt or reduce their viscosity prior to filling into the cable during cable manufacturing. Conventional moisture barrier materials have the following drawbacks because they solidify or become highly viscous while shrinking when cooled after filling.

(1) Due to shrinkage, gaps occur in the economic surface between the moisture barrier layer and the moisture barrier material or at the interface between the moisture barrier material and the optical fiber in the cable core, and as a result, when moisture enters the cable, the longitudinal gap of the cable The water will run along.

(2) Fibers are thin and flexible and therefore can be easily bent, but are constrained by moisture blocking materials that quickly become viscous or solidified after cooling. Moreover, shrinkage of this material leads to micro bending of the fiber, resulting in increased light transmission loss. Particularly when the cable is used during the winter or in cold weather, the material shrinks more markedly to increase the binding force and thus the light transmission loss.

(3) Since moisture barrier material is difficult to remove from the cable after solidification, it is difficult to make the cable connection highly precise or it takes a long time.

It is an object of the present invention to provide a new water resistant fiber optic cable.

It is another object of the present invention to provide a water resistant optical fiber cable having a special moisture barrier material which is easy to charge the inside of the cable at room temperature and can exert an excellent moisture barrier effect.

The present invention provides an optical fiber cable composed of a moisture barrier layer, an optical fiber located inside the moisture barrier layer, and a moisture barrier material filling a space between the moisture barrier layer and the optical fiber, wherein the moisture barrier material comprises 3 × 10 ⁴ packets. Processing of 85 to 475 (measured at 25 ° C in accordance with JIS K2220-1980,5.30) with an apparent viscosity of less than azure (measured at 40 ° C and 10 sec ^-1 shear rate in accordance with JISK2220-1980,5,15) It has permeability.

1 and 2 are cross-sectional views showing embodiments of the present invention.

Referring to FIGS. 1 and 2, like reference numerals denote like parts, and an optical fiber unit 1 is shown, each of which is a single optical fiber or strands of a plurality of optical fibers, and a tension member 2. A moisture barrier layer 3 formed by enclosing the assembly of the optical fiber unit 1 longitudinally with a moisture barrier tape or by winding a moisture barrier tape around the assembly, the sheath 4 and the moisture barrier layer. (3) It is composed of a moisture barrier material (5) to fill the space inside.

The moisture barrier tape may be a tape made of a metal such as copper, aluminum, lead, or the like, or a high organic polymer having high moisture barrier ability, such as polyvinylidene chloride, polychlorofluoroethylene, bidirectionally oriented polypropylene, or the like. The moisture barrier tape is preferably a single-sided adhesive layer which is to be bonded to the tapes at the overlapping portion, but more preferably a double adhesive layer having an adhesive layer for adhering the moisture barrier layer 3 to the exterior 4.

The sheath 4 itself may have a simple moisture barrier structure, or may be made of a moisture barrier material (waterproof material) so as to act as a moisture barrier layer instead of the moisture barrier layer 3.

The tension member 2 is not always necessary, but is preferably used because the optical fiber generally has low mechanical strength. As shown in FIGS. 1 to 2, tension members 2 of various structures and materials can be used.

)와 같은 유기중합체섬유의 끈형태로 된 장력부재(11)주위에 배치된 6개의 광섬유 조립체(12)를 포함한다. 지지테이프(13)가 조립체 주위에 감겨져 있다. 전기절연케이블이 장력부재(2)로서 사용되며, 그 주위에는 8개의 광섬유단위(1)가 배열되어 있다.Referring to FIG. 1, the optical fiber unit 1 is Kevlar.

And six optical fiber assemblies 12 disposed around the tension member 11 in the form of a string of organic polymer fibers. A support tape 13 is wound around the assembly. An electrically insulated cable is used as the tension member 2, and eight optical fiber units 1 are arranged around it.

Referring to FIG. 2, a tension member 2 composed of braided wires is provided with a spacer made of an organic polymer such as polyethylene, polypropylene, nylon, or the like. The spacer 7 has a plurality of helical grooves on its outer periphery that are slightly larger in width and depth than the outer diameter of the optical fiber 12. The optical fiber is buried in the moisture blocking material filled in the grooves and provided to each groove 21. A supporting tape 6 having the above-described structure is wound around the spacer 7 in the same manner as described above. Since the optical fiber has such a structure, each optical fiber 12 has its three surfaces protected by the wall of the spacer 7 defining its groove 21, surrounded by a moisture barrier material, and the outside of the support tape. (6) is supported. Therefore, the optical fiber 12 is sufficiently protected from external force.

The moisture barrier material to be used in the present invention has a process penetration of 85 to 475 as measured at 25 ° C. according to JIS K2220-1980.

Materials with less than 85 workability are hard and therefore need to be softened by heating prior to filling. Such materials tend to solidify at low temperatures.

On the other hand, a material with a work permeability of 475 or more has excessive fluidity, and therefore, if it is included in a cable installed in an inclined or vertical position, the material flows downward in the cable, causing pressure in the cable portion at the lower position, and thus rupturing in the sheath. It is possible to cause cavities or to create cavities in the upper cable part. Therefore, a moisture barrier material having a process permeability of preferably from 100 to 450, more preferably from 100 to 450, most preferably from 200 to 400 is used at 25 ° C. More preferred greases are those having a process permeability of 100 to 450, in particular from 120 to 385 at 25 ° C, and also having a raw permeability of at least 100 at -30 ° C.

In addition to the above, the moisture barrier material to be used in the present invention has an apparent viscosity measured at 40 ° C. and a shear rate of 10 seconds ⁻¹ or less according to JIS K2220-1980, 5.15 of 3 × 10 4 poise or less. From a commercial point of view, it is very important to manufacture the optical fiber cable of the present invention without problems and with high efficiency. In order to achieve this goal, the moisture barrier material should have the low apparent viscosity described above. Materials with apparent viscosities of 3x10 4 poise or higher do not need to be charged into the cable at high pressures, which results in micro bending of the optical fiber in the cable, resulting in increased light transmission loss. On the other hand, in order to avoid such a problem, when the high-viscosity material is isolated at low pressure, the inner space of the cable is insufficiently filled with the material, and the moisture barrier property of the cable becomes poor.

For the above reason, in the present invention, a low viscosity moisture barrier material having an apparent viscosity of less than 27000 poises, more than less than 25000 poises is preferably accommodated. Considering the ease of handling of materials and the ease of cable manufacture and the quality of the cables produced, the most preferred moisture barrier materials have a process permeability of 150 to 350 at 25 ° C. and an apparent viscosity of 100 to 6,000 c.St.

In the present invention, as long as the above requirements are satisfied, various kinds of chemicals can be used as the moisture barrier material. Of these, grease is a preferred embodiment of the moisture barrier material. It is generally known that grease is defined as a dispersion in which a solid thickener is dispersed in the colloidal or micelle phase in a natural or synthetic organic liquid body. The greases constituting the moisture barrier material useful in the present invention are defined as described above, and have a specific process permeability and apparent viscosity, and are excluded from those that are too soft, too hard or too viscous.

Examples of useful natural or aqueous organic liquids are as follows.

(1) natural organic liquids

1.1) Oil derived from petroleum such as transformer oil, spindle oil, electric insulating oil, machine oil, etc.

1.2) Animal and vegetable oils such as rosin oil, castor oil, olive oil and gorilla oil.

(2) Synthetic organic liquid

2.1) hydrocarbon oils such as polybutene, α-olipine oligomer, paraffin chloride, liquid rubber and the like.

2.2) Glycols such as polyethylene glycol and polypropylene glycol.

2.3) Dioctyl sebacic acid ester, dioctyladipic acid ester and other esters used as plasticizers for polyvinyl chloride.

2.4) Other synthetic oils such as di-2-ethylhexylphthalate, polydimethylsiloxane, polytrifluorochloroethylene and the like.

From the viewpoint of producing grease which can be easily filled into the optical fiber among the natural and synthetic liquids, those having a kinematic viscosity of 4 to 10,000 c.St and 20 to 1,000 c.St at 40 ° C. are preferably used.

Examples of useful midpoints are as follows.

1) metal soaps

For example, organic acid salts of Ba, Sr, Zn, Pb, Cd, K, Na, Ca, Li, Al and similar metals, preferred organic acids are carbon atoms such as formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, benzoic acid, etc. Is 1 to 7, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachic acid, behenic acid, seric acid, montanic acid, oleic acid, linoleic acid, linolenic acid, azelaic acid, seba Natural acids, such as those having 8 to 36 carbon atoms such as succinic acid and phthalic acid, and palm fatty acids, resin fatty acids, castor fatty acids, rapeseed fatty acids, fish oil fatty acids, whale oil fatty acids, and hydrogenated fatty acids thereof.

Examples of metal soaps include aluminum stearate benzoate, sodium behenate acetate, barium stearate acetate, calcium stearate butyl acetate, 12-hydroxy-stearic acid caproate lithium, sodium salt of hydrogenated resin fatty acid, Barium salt of hydrogenated resin half acid, calcium salt of hydrogenated castor fatty acid, lithium salt of hydrogenated perma fatty acid and hydrogenated rapeseed fatty acid, potassium salt of acitic acid and resin fatty acid, acetic acid and hydrogenated Calcium salt of palm fatty acid, sodium salt of butyl acid and palm fatty acid and rapeseed fatty acid, aluminum benzoate behenate, aluminum salt of benzoic acid and hydrogenated fish oil fatty acid.

2) non-soap

2.1) Urea compounds such as compounds represented by the following general formula

Of R ₁ NH- (CONH-R2-NH) n-CONH-R ₃

In this formula, R ₁ , R ₂ , R ₃ are hydrocarbon groups and the value of n is a positive integer of 1 to 6. Urea compounds are obtained, for example, by reacting monoamines and / or monoisocyanates with diamines and / or diisocyates. R ₁ in the formula in a reaction with R ₂ is a residue of the monoamine or monoyi SOCCIA lactate, R ₂ is the residue of a diamine or a diimide SOCCIA press.

Preferred carbon numbers of R ₁ and R ₃ are 3 to 22, in particular 5 to 22. Preferred carbon number of R <_2> is 2-22, especially 3-15.

Urea compounds with n greater than 6 are too viscous, and greases containing such urea compounds are too viscous. The preferred value of n is therefore 1 to 4, in particular 1 to 2.

R ₁ , R ₂ and R ₃ are saturated unsaturated aliphatic, aromatic or alicyclic hydrocarbon groups.

Silye of R ₁ or R ₃ is such as alkyl, alkenyl, aryl, arylalkyl, cycloalkyl, cycloalkylalkyl, silye as the R ₂ is a divalent group corresponding to the examples of R ₁ or R _3. Examples of monoamines include aliphatic amines such as octylamine, nonylamine, decylamine, tridecylamine, stearylamine, and laurylamine, and alicyclic amines such as cyclohexylamine, dimethylcyclohexylamine, butylcyclohexylamine, and the like. And aromatic amines such as xyldine, phenylpropylamine, phenylbutylamine, toluidine and the like. Examples of diamines include aliphatic diamines such as hexanediamine, octanediamine, hexadecadiamine, and alicyclic diamines such as diaminocyclohexane, diaminocyclooctane, dicyclohexylmethanediamine, and the like, such as phenylenediamine and benzidine. Aromatic diamines;

Examples of monoisocyanates include aliphatic monoisocyanates such as hexyl isocyanate, hexadecyl isocyanate and the like, alicyclic monoisocyanates such as cyclohexyl isocyanate and cyclooctyl isocyanate, and aromatic monoisocyanates such as phenyl isocyanate and tolyl isocyanate.

Examples of diisocyanates include aliphatic diisocyanates such as hexane diisocyanate, decane diisocyanate and the like, and aromatic diisocyanates such as phenylene diisocyanate, diphenylmethane diisocyanate and the like.

The reaction of the isocyanate with the amine can be carried out in various ways. As an example, a required amount of diamine or monoamine is added to the above-mentioned organic liquid in which a required amount of diisocyanate and, if necessary, monoisocyanate is dissolved, and the mixture is stirred well at a reaction temperature of 10 to 200 캜.

2.2) Amino acid-type oil gelling agents such as N-laucoyl-L-glytamic acid-1α, 1 "-n-butylamide, and the like.

2.3) cellulose derivatives, such as quaternary ammonium salts of cellulose, fatty acid esters of daxtrins, and the like.

2.4) Metal oxide gels, such as aluminum oxide gels, titanium oxide gels, silica gels, and the like.

2.5) Other thickeners such as bentonite, phthalocyanine, organic resin powder and the like.

If the thickener is used in excess, the apparent viscosity and process permeability of the grease are too large and too small, respectively. On the other hand, if the amount of the middle agent is too small, the grease becomes fluid in the cable even at low temperatures, causing the above problems. The amount of the thickening agent to be used for the production of grease that satisfies the above two conditions varies somewhat depending on the type and viscosity of the organic liquid as well as the type of the thickening agent, but is generally 1 to 50 parts by weight, preferably 2 per 100 parts by weight of the organic liquid. To 40 parts by weight, more preferably 3 to 35 parts by weight.

Examples of greases to be suitably used in the present invention are as follows.

1) A grease containing at least one selected from the group consisting of sodium soap, potassium soap and calcium soap as an emphasis, sodium salts of resin fatty acids, sodium behenate, potassium salts of rapeseed fatty acids, acetic acid And a grease containing at least one component selected from the group consisting of a potassium salt of a resin fatty acid, a hydrogenated castor fatty acid calcium salt, and the like as a middle agent.

Greases of this group have the advantage of water absorption. Thus, even when the sheath of the cable is locally ruptured and water penetrates into the cable, the moisture barrier material containing this group of grease absorbs and retains the water, preventing water from flowing through the cable.

2) A grease containing as an organic liquid at least one selected from the group consisting of glycol and hydrocarbon oil containing less than 1% by weight of one component other than carbon and hydrogen.

Examples of these organic liquids are polyethylene glycol, polybutene, α-olefin oligomer, and the like, and examples of these greases include silica gel grease, lithium soap grease, aluminum soap grease, urea grease and the like.

Since greases in these groups have low polarity, they are excellent in compatibility with urethane resins, epoxy resins, and the like, and thus are suitably used for cables in which each optical fiber has an outer layer containing such a resin.

3) Grease containing a metal soap and an organic liquid, preferably mineral oil, having a pour point of less than 0 ° C. and a raw permeability of 85 or more at 0 ° C., or 2 to 1000 c.St. 2 to 15 parts by weight of an organic liquid having a viscosity of 2 to 15 parts per 100 parts of an organic liquid containing lithium or aluminum soap, which is a salt of an organic acid having 4 to 40 carbon atoms, and having a process permeability of 130 to 475 at 25 ° C.

Examples of these greases include lithium sebacate 12-hydroxy-stearic acid caproate grease, lithium behenate grease, aluminum benzoate stearate, and aluminum distearate.

Greases from these groups facilitate grease filling operations during cable manufacturing. After filling, they are still satisfactory in flexibility even when cooled to a low temperature below 0 ° C, so that the grease will not confine the optical fiber and the fibers will not bend in use. Moreover, the grease does not have a constant flow downward into the cable.

4) Ba, Sr, Zn, Pb, Cd of hydrocarbon oil having an aniline point of 50 to 128 ° C., preferably 60 to 120 ° C., and (a) an organic acid having 1 to 7 carbon atoms and an organic acid having 8 to 36 carbon atoms. From a metal soap comprising a soap of, K, Na, Li, Ca and Al, (b) an Al soap of benzoic acid and an organic acid having 8 to 36 carbon atoms, and (c) a metal soap of an organic acid having 8 to 36 carbon atoms. Grease containing at least one selected from 4 to 40 parts by weight per 100 parts by weight of hydrocarbon oil, a preferred example of a hydrocarbon oil is kinematic viscosity at 40 ℃ 2 to 1,000 c.St, in particular 8 to 600 c.St. There is to be.

The grease of these groups is very stable because of their ingredients. Side hydrocarbon oil and a midpoint agent are inseparably related.

Thus, by using these groups of greases, the original light transmission can be maintained for a long time.

5) The kinematic viscosity at 40 ° C. is 10 to 50,000 c.St, preferably 50 to 1,000 c.St. A urea grease containing phosphorus organic liquid and containing 1 to 30% by weight of the above-mentioned urea compound. These groups of greases are excellent in electrical insulation, and therefore are suitably used in composite cables between optical fibers and electrical insulated wires. Other useful greases were published by Hiroguchi of the Circuit in "Lubricants and Greases" (pp. 402-419, Sankyoshuppan Co., Ltd., Tokyo, Feb. 1970).

In manufacturing the optical fiber cable of the present invention, the space between the optical fiber or the optical fiber unit can be filled with a moisture barrier material in various ways.

For example, as one method, the moisture blocking material is supplied to the optical fiber unit, and the optical fiber unit is wound around the tension member or the spacer as shown in FIG. Alternatively, the optical fiber units are wound around the tension member and then the strands thus assembled are continuously dumped at a pressure of about 0.5 to 10 kg / cm 2 -G, preferably at a pressure of 1 to 5 kg / cm 2 -G. Pass into the chamber. The space between the optical fiber units is filled with a moisture barrier material while passing through the chamber. When the moisture barrier fills the space, it forces the optical fiber. However, the force is so small that it does not substantially cause micro bending of the optical fiber. This is because the moisture barrier material to be used in the present invention has a low apparent viscosity as described above.

The present invention will be described in more detail with reference to the following examples along with the comparative examples. All parts percentages are by weight and the physical properties of the materials are evaluated by the following method unless otherwise indicated.

Process penetration: JIS K2220-1980, 5.3, 25 ℃

Raw permeability: JIS K2220-1980, 5.3, at 0 ° C

Apparent viscosity: JIS K2220-1980, 5.15, 40 ℃ and 10 sec ^-1 shear rate,

Kinematic Viscosity: JIS K2283-1980,

Aniline point: JIS K2256-1980,

Pour point: JIS K2220-1980, 5.7

Water Absorption: The bottom end of the vertically positioned glass tube having a diameter of 7.2 mm and a length of 1 m was filled with a moisture barrier material to be tested, and the glass tube was filled with water to form a water column of 80 cm on the moisture barrier material. The glass tube was closed with a rubber stopper with a small through hole for pressure equalization so that moisture in the glass tube did not evaporate from the top of the glass tube. Measurements were made to determine the amount of water loss in the water column (μ1) and the amount of leaked water (μ1) from the bottom of the water barrier substance in the glass tube (hereinafter abbreviated as water leakage) after 240 hours after the formation of the water column. . Water absorption (μ1) is defined as the difference between the amount of water in the water column and the leakage of water.

Dielectric constant: JIS C2101-1982, 21

Volume resistivity: JIS C2101-1982,22

[Preparation of moisture barrier materials (WB-1 to WB-56) used in the examples]

WB-1: 250 parts of stearic acid and 500 parts of hydrocarbon oil (40 ° C., kinematic viscosity at 162.6 c.St.) were mixed and heated at 90 ° C. The mixture was removed with water dispersed in 150 parts of the same hydrocarbon oil as described above, mixed with 350 parts of the same hydrocarbon oil as described above with stirring, then heated to 220 ° C., cooled and finally milled. The Lytum soap grease thus obtained had an apparent viscosity of 2,900 poise and a permeability of 196.

WB-2: Calcium soap grease (apparent viscosity 4,700 poise, work permeability: 238) was prepared using negatively hydrogenated resin fatty acid, 1000 parts of hydrocarbon oil, 80 parts of acetic acid, and 82.5 parts of calcium hydroxide.

WB-3: 50 parts of poly-α-olefin (kinematic viscosity at 40 ° C: 86.4c.St.) was mixed with 4.5 parts of silica gel, stirred and pulverized and then mixed with 50 parts of the same poly-α-olefin as described above. Then, it was ground to obtain a silica gel grease having an apparent viscosity of 107 poises and a process permeability of 367.

WB-4: 32.5 parts hydrogenated rapeseed fatty acid, 197.5 parts hydrogenated castor fatty acid and 350 parts α-olefin oligomer (40 ° C .: kinematic viscosity at 86.4 c.St.) were mixed and heated to 90 ° C. An aqueous solution of 44.7 parts of lithium hydroxide dissolved in 70 parts of water and the mixture were mixed and saponified with stirring. The product was heated to 150 ° C. to remove water, mixed with the same 520 parts of α-olefin oligomer as described above, heated to 220 ° C. while stirring, and gradually cooled to 4,4′-thiobis (3- Methyl-t-butyl-phenol) was mixed and pulverized to obtain a lithium soap grease having an apparent viscosity of 840 poise and a work permeability of 277.

WB-5 to WB-36: WB-5 to WB-12 shown in Table 1 and WB-13 to WB- shown in Table 2 using various materials and similar reactions used in the preparation of WB-4. 36 was prepared.

TABLE 1

TABLE 2

WB-37: Using 99.5 parts hydrogenated resin fatty acid, 1200 parts hydrocarbon oil (162.5 c.St. at 40 ° C.), 11.4 parts acetic acid and 23.3 parts calcium hydroxide, has a permeability of 338 and an apparent viscosity of 1280 poise. Was prepared, calcium soap grease having a water absorption of 125 m and a water leakage of 0 μ1.

WB-38: Process permeability using 220 parts hydrogenated rapeseed fatty acid, 85 parts hydrogenated castor fatty acid, 1,000 parts poly-α-olefin (86.5 c.St. at 40 ° C.) and 39 parts sodium hydroxide Sodium soap grease having 207, apparent viscosity of 3200 poise, water absorption of 133 µ1, and leakage of 0 µ1 was prepared.

WB-39: 300 parts of hydrogenated resin fatty acid, 1200 parts of hydrocarbon oil (162.3c.St. at 40 ° C) and 61.6 parts of calcium hydroxide, processing permeability is 205, apparent viscosity is 8,600 poise, water absorption is 143μl, And a potassium soap grease having a water leakage of 0 μl.

WB-40: 20.6 gr (80 m mole) of diphenylmethane diisocyanate was heated to 90 ° C. and dissolved in 500 g of hydrocarbon oil (101.1 c.St. at 40 ° C.). Meanwhile, 44.4 g (164 m mole) of stearylamine was dissolved in 435 g of hydrocarbon oil (484.9 c.St. at 40 ° C.) by heating to 90 ° C. These two solutions were mixed vigorously while heating to 180 ° C. The mixture was then cooled to 80 ° C. and passed through a colloid-mill to prepare urea grease.

WB-41: 25.0 gr (97 m mole) diphenylmethane diisocyanate, 13.2 gr (102 m mole) octylamine, 26.8 gr (100 m mole) stearylamine, 735 g hydrocarbon oil (kinematic viscosity at 40 ° C: 101.1c Urea grease was prepared using.

WB-42: 26.5 gr (103 m mole) diphenylmethane diisocyanate, 10.5 gr (107 m mole) cyclohexylamine, 28.4 g (105 m mole) stearylamine and 735 gr hydrocarbon oil (kinetic viscosity at 40 ° C .: 484.9c.St.) to prepare urea grease.

WB-43: 50.0 gr (194 m mole) of diphenylmethane diisocyanate, 13.8 gr (66 m mole) of chlorohexyl methane diamine, 9.4 g (96 m mole) cyclohexylamine, 27.0% (101 m mole) of stearylamine And 600 gr of hydrocarbon oil (kinematic viscosity at 40 ° C .: 218.6 c.St.).

Urea grease was prepared by WB-44: 22.2 gr (89 m mole) of myristylamine and 940 g of polydimethylsiloxane oil (kinematic viscosity at 40 ° C: 100 c.St.).

WB-45: 24.0 gr (96 m mole) diphenylmethane diisocyanate, 25.6 (96 m mole) stearylamine, 10.4 g (96 m mole) m-toluidine and 940 g polybutene (115.7 c.St. kinematic viscosity ) Was prepared urea grease.

WB-46: Urea grease was prepared using 60.5 g (242 m mole) of diphenylmethane diisocyanate, 89.5 g (484 m mole) of laurylamine, and 850 g of di-2-ethylhexyl sebacate. The properties of WB-40 to WB-46 are shown in Table 3.

TABLE 3

WB-47 to WB-56: 350 parts hydrogenated resin fatty acid (C14 to C22), 1240 parts hydrocarbon oil (kinematic viscosity at 40 ° C: 261.3c.St., pour point: -2.5 ° C), 62 parts of hydroxide WB-47 was prepared in a similar manner to the preparation of WB-1 using lithium and 10 parts of diphenylamine (antioxidant). WB-48 to WB-56 were also prepared in a similar manner to WB-47.

The components and properties of WB-47 to WB-56 are described in the labels.

Moisture barrier materials used in Comparative Examples (WB-57 to WB-60)

WB-57: Compound # 58 (melting point: 105 ° C) of witco. Co., U.S.A.

WB-58: Sodium soap grease having an apparent viscosity of 31,000 poises and a process permeability of 100, prepared using hydrogenated resin fatty acid.

WB-59: Lithium soap grease having an apparent viscosity of 33,000 poises and a process permeability of 78, prepared using rapeseed fatty acid.

WB-60: Urea grease with 35,000 poise and apparent viscosity and 150 permeability.

TABLE 4

[Examples 1 to 56, Comparative Examples 1 to 4]

의 피아노선으로 된 장력부재 주위에 감았다.(꼬았다) 이 가닥 주위에 2.6cm의 테이프간격으로 연신 폴리에틸렌테이프(두께 : 50㎛, 폭 : 2.5mm)를 감아서 외경이 약 4.0mm인 광섬유심을 제조하였다. 이와같은 광섬유심 8개를 40cm 핏치로 7개의 피아노선 가닥(각개 피아조선은 직경이 1.2mm)으로 구성된 장력부재주위에 감고, 그 전체주위에 폴리에틸렌층(외경 : 5.0mm)을 만들었다. 이와 같이 얻어진 외경 13mm의 조립체를 직경 5mm인 다수의 오리피스(구멍)를 그 내벽에 갖는 테이퍼진 실린더에 계속 통과시키고, 한편 이 오리피스를 통하여 수분차단물질을 실온으로 유지된 실린더내에 5kg/㎠ -G의 압력으로 도입하여 조립체와 유니트를 사이의 틈 및 광섬유들 사이의 틈을 충전시켰다. 두께 20㎛, 폭 55mm이고 한 표면상에 에틸렌-비닐아세테이트 공중합체 접착층을 갖는 알루미늄 적층테이프를 위해서 제조된 조립체 주위에 종방향을으로 겹쳐 감아서 수분차단층을 만들고, 다음에 두고 2.5mm의 폴리에틸렌 외장으로 피복하였다. 이와 같이하여 외경 20mm의 광섬유 케이블이 30m/분의 신속도로 연속 제조되었다.GI-type optical fiber wire with a core diameter of 50 µm and a coating diameter of 125 µm, and 6 optical fibers coated with a silicon primary coating, a silicone rubber buffer layer, and a nylon racket having an outer diameter of 0,9 mm, 1 mm at 15 cm pitch

(Twisted) A stretched polyethylene tape (thickness: 50 µm, width: 2.5 mm) was wound around the strands with a tape gap of 2.6 cm, and the outer diameter was about 4.0 mm. Shims were prepared. Eight such fiber cores were wound around a tension member consisting of seven piano wire strands (each piazo wire 1.2 mm in diameter) at a pitch of 40 cm, and a polyethylene layer (outer diameter: 5.0 mm) was formed around the entire fiber core. The 13 mm outer granule thus obtained is continuously passed through a tapered cylinder having a plurality of orifices (holes) having a diameter of 5 mm on the inner wall thereof, while through the orifice, 5 kg / cm 2 -G in a cylinder kept at room temperature. The gap between the assembly and the unit and the gap between the optical fibers were filled by introducing a pressure of. A water barrier layer was formed by winding longitudinally around an assembly prepared for an aluminum laminated tape having a thickness of 20 μm, a width of 55 mm and having an ethylene-vinylacetate copolymer adhesive layer on one surface, and then placed a 2.5 mm polyethylene. Covered with sheath. In this manner, an optical fiber cable having an outer diameter of 20 mm was continuously manufactured at a speed of 30 m / min.

The moisture barrier material WB-57 used in Comparative Example 1 is a solid at room temperature, so that the moisture barrier material used in each example and the comparative example is treated at room temperature, except that it is used in the filling process. Charged.

Table 5 shows the properties of the moisture barrier material and the moisture barrier impurities and the characteristics of the optical fiber cable used in Examples and Comparative Examples. The characteristic was measured by the following method.

Filling State of Moisture Barrier: A 10-meter-long cable specimen was cut to check the condition of moisture barrier. If there was no space in the space between the unit and the fiber that was not filled with the moisture barrier material, the moisture barrier material was evaluated to be "good". On the other hand, when the space was found, it was evaluated as "bad".

Loss-wavelength characteristics: Cable test pieces 500m in length and wound on a drum were kept at 25 ° C., and losses were measured by the CUT BACK method at 0.85 μm and 1.30 μm.

Increasing the loss by temperature: After the above measurement, the same cable test piece was tested by the CUT BACK method at 0.85㎛ at -30 ℃ and 60 ℃ and tested at -30 ℃ or 60 ℃ by 0.85㎛. The difference between the loss at and loss at 25 ° C. was measured.

Moisture barrier effect: The sheath and the moisture barrier were removed over a 25 mm length from the middle of the 2 m cable specimen. Vertical polyethylene tubes filled with water to a height of 1,000 mm were connected over the exposed cable test pieces. After the specimen was left for 14 days, the distance of water penetration from the intermediate portion was examined.

Increased loss due to bending: All the optical fibers in the cable test strip of 2m length were connected in series, and both ends of the cable were sealed with epoxy resin. The test piece was repeatedly bent 180 ° around a mandrel having a radius of 20 mm at 25 ° C., while the total loss increase was found by measuring the change in the light level of the receiver after bending 10 times and passing light through a connected optical fiber. According to the loss per fiber increase of 2m, this is equivalent.

TABLE 5a

TABLE 5b

TABLE 5c

[Comparative Examples 5 to 7]

The optical fiber cable of Comparative Example was prepared by the similar method of Comparative Examples 2 to 4, respectively, by inserting the moisture barrier material used in each Comparative Example into the cylinder at a pressure of 10 kg / cm 2 -G.

Although the inside of each cable was well filled with a moisture barrier material, the light transmission loss at 25 ° C. and 0.85 μm of each cable was about 1.0 dB / km to 3.5 dB / km larger than that of the comparative example. That is, the values of Comparative Example 5 (moisture blocking substance: WB-58), Comparative Example 6 (moisture blocking substance: WB-59) and Comparative Example (moisture blocking substance: WB-60) were 5.5 dB / km, respectively. , 8.5 dB / km, and 5.8 dB / km.

The increase in light transmission loss is certainly caused by the small bending of the optical fiber due to the high pressure of the moisture barrier material during the cable manufacturing process.

Claims (8)

It consists of a moisture barrier layer (3), at least one optical fiber (12) located inside the moisture barrier layer, and a moisture barrier material (5) that fills the space between the moisture barrier layer and the optical fiber, which is 25,000 poazumi Fiber optic cable, characterized by having a permeability of the bay (measured at 25 ° C. according to JIS K2220-1980, 5.15). The optical fiber cable according to claim 1, wherein the moisture barrier material has an apparent viscosity of 100 to 6,000 poises and a process permeability of 150 to 350. The optical fiber cable according to claim 1, wherein the moisture barrier material is a grease containing at least one component selected from the group consisting of sodium soap, potassium soap: and calcium soap as a middle agent. The optical fiber cable according to claim 1, wherein the moisture barrier material is a grease containing at least one organic liquid selected from the group consisting of glycol and hydrocarbon oil containing less than 1% by weight of one component other than carbon and hydrogen. 2. The grease of claim 1, wherein the moisture barrier material comprises a metallic soap and an organic liquid having a pour point of less than 0 ° C. and a crude permeability of greater than or equal to 85 at 0 ° C., and from 2 to 1,000 c. It consists of an organic liquid having a viscosity of 2 to 15 parts by weight per 100 parts by weight of the organic liquid of lithium or aluminum soap which is a salt of an organic acid having 4 to 40 carbon atoms and selected from the group consisting of grease having a process permeability of 130 to 475 at 25 ℃ It is a grease, the optical fiber cable. The method of claim 1, wherein the moisture barrier material is Ba, Sr, Zn, Pb, Cd of a hydrocarbon oil having an aniline point of 50 to 128 ℃, (a) an organic acid having 1 to 7 carbon atoms and an organic acid having 8 to 36 carbon atoms Hydrocarbon oil selected from metal soaps of soaps of K, Na, Li, Ca or Al, (b) Al soaps of benzoic acid and organic acids having 8 to 36 carbon atoms, and (c) organic acids having 8 to 36 carbon atoms. And a grease consisting of at least one metal soap at 4 to 40 parts by weight per 100 parts by weight. The optical fiber cable according to claim 1, wherein the moisture barrier material is urea grease containing 1 to 30% by weight of urea compound and an organic liquid having a kinematic viscosity of 10 to 50,000 c.St. at 40 ° C. 5. The optical fiber cable according to claim 4, wherein each optical fiber has an outer layer composed of a component selected from the group consisting of urethane resin and epoxy resin.

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