JP5730792B2 - Fiber optic cable - Google Patents

Description

  The present invention relates to a so-called indoor cable, which is an optical fiber cable suitable for laying work in a pipe.

  Indoor cables are often routed through existing pipes for electric wires occupied by existing metal cables and optical cables. As an indoor cable laying method, a method of inserting an indoor cable by pushing the indoor cable into a pipeline may be employed. Therefore, it is necessary that the sheath of the indoor cable has low friction.

  Moreover, since an indoor cable passes through the inside of a building, high flame retardance is calculated | required. In order to impart flame retardancy, halides such as chlorine compounds and bromine compounds have been added to the resin of the sheath. There is also a need for flame retardancy.

  For example, an optical drop cable is disclosed in which a sheath is formed from a non-halogen composition obtained by blending only red phosphorus as a flame retardant component into linear low-density polyethylene or high-density polyethylene (Patent Document). 1).

JP 2009-229518 A

  However, in general, the conventional single-core indoor cable has been a technical field that is required to pass the 60-degree inclined flame retardant test specified in JIS C 3005. With the internationalization, vertical flame retardants are also required.

  The optical drop cable described in Patent Document 2 has red phosphorus added as a flame retardant component and has passed the 60-degree inclined flame retardant test defined in JIS C 3005. In addition, since the sheath color is reddish, it is difficult to freely color the sheath.

  The present invention has been made in view of the above-described problems, and the object of the present invention is to use a non-halogen material, and a resin composition excellent in low friction, flame retardancy, coloring freedom, etc. It is to obtain the used optical fiber cable.

In order to achieve the above-mentioned object, the following invention is provided.
(1) An optical fiber cable having at least an optical fiber core and a sheath covering the optical fiber core, wherein the sheath comprises (a-1) an ethylene-vinyl acetate copolymer and / or (a-2). 40 to 80% by mass of an ethylene- (meth) acrylic acid ester copolymer, (b-1) a polyolefin modified with an unsaturated carboxylic acid or a derivative thereof and / or (b-2) ethylene- (meth) acrylic acid 100 parts by mass of the resin component (A) containing 20 to 60% by mass of the copolymer and 10 to 50% by mass of the resin having a polypropylene portion, (d) 5 silicon resin as a lubricant To 15 parts by mass, (e) 90 to 250 parts by mass of magnesium hydroxide as a flame retardant, and (c) ethylene / α-olefin copolymer weight in the resin component (A) It includes a body less than 30 wt%, as the component (b-1), and characterized in that it comprises containing the maleic acid-modified polyethylene and maleic acid-modified polypropylene, the flame-retardant resin composition containing no crosslinking agent Fiber optic cable.
(2) In the flame-retardant resin composition, with respect to 100 parts by mass of the resin component (A), 0 to 20 parts by mass of titanium oxide and 0 to 8 parts by mass of red phosphorus are contained, and the content of the titanium oxide is The optical fiber cable as set forth in (1), which is equal to or more than the content of red phosphorus.
(3) The optical fiber cable according to (1) or (2), wherein a dynamic friction coefficient of the flame retardant resin composition is 0.10 to 0.25.
(4) The optical fiber cable according to any one of (1) to (3), further including a tension member in the sheath.

  According to the present invention, it is possible to obtain an optical fiber cable using a non-halogen material and a resin composition that is excellent in low friction, flame retardancy, and colorability as a sheath.

Sectional drawing which shows the optical fiber cable 1 which concerns on embodiment of this invention. Sectional drawing which shows the optical fiber cable 1a which concerns on embodiment of this invention. Schematic which shows the method of measuring the dynamic friction coefficient between optical fiber cables.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic sectional view showing an embodiment of the present invention. The optical fiber cable 1 of the present invention includes an optical fiber core wire 3 and a sheath 5 that covers the optical fiber core wire 3.

  The optical fiber core wire 3 is an optical fiber strand coated with a primary coating (primary) and, if necessary, a secondary coating (secondary) immediately after drawing of an optical fiber made of glass or resin. Further, in FIG. 1, a single optical fiber core wire 3 having one optical fiber strand is illustrated, but two or four optical fiber core wires 3 or four optical fiber core wires 3 are connected. It may be used. The primary coating and the secondary coating are formed using a resin composition such as an ultraviolet curable resin, for example, an ultraviolet curable urethane acrylate, and cured by irradiation with ultraviolet rays.

The flame retardant resin composition used as the sheath 5 has the following characteristics.
40 to 80% by mass of (a-1) ethylene-vinyl acetate copolymer and / or (a-2) ethylene- (meth) acrylic acid ester copolymer
(B-1) 20 to 60% by mass of a polyolefin modified with an unsaturated carboxylic acid or a derivative thereof and / or (b-2) an ethylene- (meth) acrylic acid copolymer
For 100 parts by mass of the resin component (A) containing
(D) containing 5 to 15 parts by mass of a silicone resin as a lubricant,
(E) containing 90 to 250 parts by mass of magnesium hydroxide as a flame retardant,
Content of resin which has the polypropylene site | part in the said resin component (A) is 10-50 mass%.

(Resin component (A))
The resin component (A) contains (a-1) an ethylene-vinyl acetate copolymer and / or (a-2) an ethylene- (meth) acrylic acid ester copolymer alone or in total of 40 to 80 mass. %, Preferably 45 to 70% by mass, more preferably 40 to 60% by mass. If the content is too small, the flame retardancy deteriorates, and if the content is too large, it becomes too soft.

  The resin component (A) includes (b-1) a polyolefin modified with an unsaturated carboxylic acid or a derivative thereof and / or (b-2) an ethylene- (meth) acrylic acid copolymer, either alone or in total. Although it contains 20-60 mass%, it is preferable to contain 20-40 mass%. If the content is too small, the mechanical properties are inferior. If the content is too large, the material becomes soft and the frictional force is large. In addition, it is preferable to mix and use polyethylene and polypropylene as the component (b-1) in order to improve flame retardancy.

  Further, the resin component (A) preferably contains 30% by mass or less of (c) an ethylene / α-olefin copolymer. Since the ethylene / α-olefin copolymer is inexpensive, the cost of the flame retardant resin composition can be reduced by adding the ethylene / α-olefin copolymer to such an extent that the characteristics are not affected. On the other hand, when there is too much content, a problem will arise in a flame retardance.

  Moreover, although resin content (A) is 10-50 mass% of content of resin which has a polypropylene site | part, it is preferable that it is 14-45 mass%. Therefore, polypropylene may be added in addition to the aforementioned (a-1), (a-2), (b-1), (b-2), and (c). When there is too little content of the resin which has a polypropylene site | part, it will become too soft, and when there is too much content, it will become hard too much and also a flame retardance will deteriorate.

(Additional material to resin component (A))
The resin component (A) is contained in an amount of 5 to 15 parts by mass of the silicon resin as the lubricant (d) with respect to 100 parts by mass, and preferably 5 to 12 parts by mass. If the content is too small, the friction coefficient is increased, and if the content is too large, the flame retardancy is deteriorated.

  Although (e) 90-250 mass parts of magnesium hydroxide is contained as a flame retardant with respect to 100 mass parts of resin component (A), it is preferable to contain 90-230 mass parts. If the content is too small, the flame retardancy is deteriorated, and if the content is too large, the mechanical strength is deteriorated. Magnesium hydroxide is more likely to disperse in the resin component (A) when it is surface-treated, and therefore the surface is preferably subjected to silane treatment (surface treatment with a silane coupling material) or phosphate ester treatment.

  Moreover, you may contain 0-20 mass parts of titanium oxides, and 0-8 mass parts of red phosphorus with respect to 100 mass parts of resin components (A) as needed. Red phosphorus is added as necessary to improve flame retardancy. However, since the flame retardant resin composition is colored red when red phosphorus is added, the degree of coloring can be reduced by adding the same amount or more of white titanium oxide.

  Moreover, you may add 2-10 mass parts of zinc compounds with respect to 100 mass parts of resin components (A) as needed. Examples of the zinc compound include zinc stannate, zinc borate, and zinc sulfate. When a zinc compound is added, flame retardancy is improved.

(About optical fiber cable 1a)
As an actual indoor cable, there is an optical fiber cable 1a as shown in FIG. The optical fiber cable 1a has a tension member 7 in addition to the optical fiber core wire 3 in a sheath 5a. In addition, although the optical fiber core wire 3 is illustrated with a single core, it may actually be two cores, four cores, eight cores or the like.

  The tension member 7 is disposed in parallel to the longitudinal direction of the optical fiber core wire 3. The center of the tension member 7 is positioned so as to be substantially flush with the center of the optical fiber core wire 3. The tension member 7 is made of, for example, an aramid fiber bundle or FRP (fiber reinforced plastic) using an aramid fiber as a reinforcing fiber, or a steel wire. The tension member 7 is used to protect an optical fiber having inferior mechanical strength when it receives an external force in its longitudinal direction.

  A notch 9 can be provided on the outer surface of the sheath 5a. The notches 9 are notches provided as needed on both surfaces of the outer surface of the sheath 5a facing each other. If the notch 9 is provided, the sheath 5a can be easily torn during cable laying or the like, and the internal optical fiber core wire 3 can be easily taken out.

(Effect of the optical fiber cable 1 according to the present invention)
Since the optical fiber cable 1 according to the present invention contains a silicone resin in the sheath and sufficiently contains polypropylene in the resin component (A) that is the base resin, the optical fiber cable 1 is excellent in slip characteristics.

  The optical fiber cable 1 according to the present invention is excellent in flame retardancy by adding a large amount of magnesium hydroxide even though it does not contain a halogen compound.

  The optical fiber cable 1 according to the present invention can achieve sufficient flame retardancy without adding red phosphorus. In addition, when red phosphorus is added, it is added together with titanium oxide so that the sheath is not colored red.

Hereinafter, the present invention will be specifically described using examples and comparative examples.
[Examples and Comparative Examples]
Tables 1 and 2 show the content of each component of the resin compositions of Examples and Comparative Examples.
In Examples and Comparative Examples, all the components were dry blended at room temperature and heated and kneaded at 200 ° C. using a Banbury mixer to produce each flame retardant resin composition.

Next, one single optical fiber core wire with a diameter of 0.25 mm and two steel wires with a diameter of 0.5 mm were extrusion-coated with each flame retardant resin composition as a sheath material, and the outer diameter A 1.6 mm × 2.0 mm optical fiber cable was obtained.
The following tests and evaluations were performed on the obtained optical fiber cable, and the obtained results are shown in Tables 1 and 2.

(1) Shore D hardness Type D durometer hardness (Shore D hardness) based on JIS K 7215 was measured using a sheet obtained by heating and pressing a flame-retardant resin.

(2) Sheath coloring property The coloring of the sheath was confirmed visually. The white one was accepted and the one with some color was rejected.

(3) Tensile test The flame-retardant resin composition was heat-press molded to produce a sheet having a thickness of 1.0 mm ± 0.15 mm. A dumbbell No. 2 type test piece based on JIS K 7113 was produced from this sheet and subjected to a tensile test. The test was performed at 25 mm between marked lines and a tensile speed of 200 mm / min, and the tensile strength (also described as TS) and tensile elongation (also described as EL) in Tables 1 and 2 were determined. The tensile strength is preferably 4.9 MPa or more, and the tensile elongation is preferably 100% or more.

(4) Dynamic friction coefficient measurement test FIG. 3 is a schematic view showing a method for measuring the dynamic friction coefficient between optical fiber cables. Specifically, two 150 mm long optical fiber cables 15 are arranged adjacent to each other in parallel on the base 10, and a 300 mm long optical fiber cable 20 as a sample for measuring the friction coefficient is stacked thereon. On the sample (measurement sample) optical fiber cable 20, the above-mentioned 150 mm long optical fiber cables 15 and 15 are further piled up as shown in FIG. At this time, the same optical fiber cables 15 and 20 as those of the present invention are used.
Thereafter, a holding plate 12 that slides up and down while being guided by a plurality of slide guides 11 provided vertically on the base 10 is placed in parallel with the base 10.
Next, the weight 13 is placed on the holding plate 12, and a constant load of 19.6N is applied in the direction of the arrow. In this state, the sample optical fiber cable 20 is pulled out in the forward direction at a speed of 500 mm / min using the load cell.
At this time, as a friction force (pull-out force) F _D, past the peak frictional force at the beginning motion adopts a value at the position of 60mm from the point showing the minimum point, the dynamic friction coefficient μ = F _D /19.6N Asked. The number of samples n was n = 3.
The test environment was a temperature of 23 ± 2 ° C. and a humidity of 50 ± 10%.
By the way, the optical fiber cables 15 and 20 were replaced every time the test was completed once (n = 1).
If the dynamic friction coefficient μ is 0.25 or less, the lineability to the pipeline is extremely excellent.

(5) Inclined flame retardant test The manufactured optical fiber cable was subjected to a 60 degree inclined combustion test based on JIS C 3005. After supporting the sample with a length of 300 mm collected from the finished product by inclining 60 degrees with respect to the horizontal, applying the tip of the reducing flame to the position 20 mm from the lower end of the sample until burning, and gently removing the flame The thing that self-extinguishes was accepted.

(6) Single-line flame retardant test The single-line flame retardant test based on IEC603332-1 was done with respect to the produced optical fiber cable.
Hold the 600 mm long cable vertically at the upper and lower supports, and apply the flame of the burner to the cable at a position of 475 ± 5 mm from the upper support and at an angle of 45 ° for 1 minute. After that, the burner was removed, the flame was extinguished, and the carbonized portion was examined.
When the distance from the upper support part to the carbonized part was 50 mm or more at the upper part of the carbonized part and 540 mm or less at the lower part (β) of the carbonized part, the result was good (◯).

(7) Multi-strip vertical flame retardant test A multi-strip vertical flame retardant test based on IEC60332-3 was performed on the manufactured optical fiber cable.
In this test, a specified number of cables were installed in a ladder-like tray installed vertically in a large enclosure in the specified manner, and the cables were burned from the bottom of the tray with a burner (flame contact time 20 minutes). Evaluate the spread of fire upward. The pass / fail criterion for the test is that the combustion length after flame removal is 250 cm or less above the burner.

(8) Vertical Tray Flame Retardancy Test The IEEE Std. A vertical tray flame retardant test based on 383 was conducted.
A specified number of cables are laid on a ladder-like vertically installed tray by a specified method, and the cables are burned by a specified burner from below the tray, and the spread of fire to the upper side of the tray is evaluated. The burner output is about 20 kW and the test time is 20 minutes. In the combustion test, the damage length was measured, and those having a damage length of 1800 mm or less were accepted (◯), and those exceeding 1800 mm were rejected (x).

In addition, as each component, the following were used.
(01) EVA (VA content 41%) (component (a-1))
Product name: V9000 (Mitsui DuPont Polychemical)
(02) EVA (VA content 17 wt%) (component (a-1))
Product Name: V5274 (Mitsui DuPont Polychemical)
(03) EEA (EA content 15 wt%) (component (a-2))
Product Name: Lexpearl A1150 (Nippon Polyethylene)
(04) Maleic acid-modified polyethylene (component (b-1))
Product Name: L6100M (Nippon Polyethylene)
(05) Maleic acid-modified polypropylene (component (b-1))
Product name: Admer QE800 (Mitsui Chemicals)
(06) Ethylene-methacrylic acid copolymer (component (b-2))
Product name: Nuclel 1207C (Mitsui DuPont Polychemical)
(07) Metallocene-catalyzed polyethylene 1 (component (c))
Product name: Kernel KF360T (Nippon Polyethylene)
(08) Metallocene-catalyzed polyethylene 2 (component (c))
Product name: Umerit 2525F (Ube Industries)
(09) Polypropylene trade name: BC3A (Nippon Polypropylene)
(10) Ultra high molecular weight silicone 1 (component (d))
Product name: CF9150 (Toray Dow Corning)
(11) Ultra high molecular weight silicone 2 (component (d))
Product name: X-22-3043 (Shin-Etsu Chemical)
(12) Styrene elastomer product name: Septon 4077 (Kuraray)
(13) Product name of process oil: PW-90 (Idemitsu Oil)
(14) Zinc stannate Product name: Alkanex ZHS (Mizusawa Chemical)
(15) Titanium oxide Trade name: CR-60 (Ishihara Sangyo)
(16) Red phosphorus trade name: Nova Excel 140F (Rin Chemical Industry)
(17) Silane-treated magnesium hydroxide Brand name: Kisuma 5L (Kyowa Chemical)
(18) Magnesium hydroxide treated with phosphate ester Brand name: Kisuma 5J (Kyowa Chemical)

  In Examples 1-8, since the flame-retardant resin composition used for the sheath was within the specified range, it passed various evaluations and tests.

In Comparative Example 1, since the content of polypropylene in the resin component (A) was 5% by mass, polypropylene was insufficient and the dynamic friction coefficient was high.
In Comparative Example 2, red phosphorus was added, but titanium oxide was not added at all, so the sheath was colored.
In Comparative Example 3, since the amount of (d) silicon resin added to the resin component (A) was small, the dynamic friction coefficient was high.
In Comparative Example 4, since (a-1) and (a-2) are not included at all, and (c) the amount of the ethylene / α-olefin copolymer is excessive, it is difficult to perform a test other than the gradient flame retardant test. It failed the flame test.
In Comparative Example 5, the amount of (a-1) is excessive as 85% by mass in the resin component (A), and the amount of (b-1) and (b-2) is 15% in the resin component (A). %, The coefficient of dynamic friction was high.
In Comparative Example 6, since the amount of (b-1) and (b-2) was insufficient with 5% by mass in the resin component (A), the tensile elongation was low.
In Comparative Example 7, since the amount of (b-1) and (b-2) is excessive as 65% by mass in the resin component (A) in total, the flame retardant test other than the gradient flame retardant test was rejected. there were. Moreover, since the titanium oxide was added in the same amount as red phosphorus, it passed the sheath coloring.
In Comparative Example 8, since the amount of (d) the silicone resin was insufficient, the dynamic friction coefficient was high even if red phosphorus was included.
In Comparative Example 9, since the amount of (d) the silicone resin was excessive, the flame retardant test other than the gradient flame retardant test was rejected.
In Comparative Example 10, since the content of (e) magnesium hydroxide was insufficient, the flame retardant test other than the gradient flame retardant test was rejected.
In Comparative Example 11, since the content of (e) magnesium hydroxide was excessive, the tensile elongation was low.
In Comparative Example 12, red phosphorus was added, but titanium oxide was not added at all, so the sheath was colored.
In Comparative Example 13, since the amount of titanium oxide was excessive, the flame retardant test other than the inclined flame retardant test was rejected.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to such examples. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the technical idea disclosed in the present application, and these are naturally within the technical scope of the present invention. Understood.

DESCRIPTION OF SYMBOLS 1, 1a ... Optical fiber cable 3 ... Optical fiber core wire 5, 5a ... Sheath 7 ... Tension member 9 ... Notch 10 ... Base 11 ... Slide guide 12 ... Restraining plate 13 ......... Weight 15 ......... Optical fiber cable 20 ......... Optical fiber cable

Claims (4)

In an optical fiber cable having at least an optical fiber core and a sheath covering the optical fiber core,
The sheath is
40 to 80% by mass of (a-1) ethylene-vinyl acetate copolymer and / or (a-2) ethylene- (meth) acrylic ester copolymer,
(B-1) contains 20 to 60% by mass of a polyolefin modified with an unsaturated carboxylic acid or a derivative thereof and / or (b-2) an ethylene- (meth) acrylic acid copolymer,
For 100 parts by mass of the resin component (A) in which the content of the resin having a polypropylene portion is 10 to 50% by mass,
(D) containing 5 to 15 parts by mass of a silicone resin as a lubricant,
(E) containing 90 to 250 parts by mass of magnesium hydroxide as a flame retardant,
The resin component (A) contains (c) an ethylene / α-olefin copolymer of 30% by mass or less,
An optical fiber cable comprising a flame retardant resin composition containing maleic acid-modified polyethylene and maleic acid-modified polypropylene as the component (b-1) and containing no crosslinking material . In the flame-retardant resin composition, with respect to 100 parts by mass of the resin component (A), 0-20 parts by mass of titanium oxide, 0-8 parts by mass of red phosphorus,
The optical fiber cable according to claim 1, wherein the titanium oxide content is equal to or greater than the red phosphorus content.   The optical fiber cable according to claim 1 or 2, wherein a dynamic friction coefficient of the flame retardant resin composition is 0.10 to 0.25.   The optical fiber cable according to claim 1, further comprising a tension member in the sheath.

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