JP6456722B2 - Flame retardant resin composition, and cable and optical fiber cable using the same - Google Patents

Description

  The present invention relates to a flame retardant resin composition, a cable using the same, and an optical fiber cable.

  Polyvinyl chloride resin (PVC) has been widely used as a resin used for covering electric wires and the like. Polyvinyl chloride resin has excellent processability, excellent chemical resistance and flame retardancy, but has a drawback of generating toxic gas during combustion.

  On the other hand, a flame retardant resin composition obtained by adding a non-halogen flame retardant to a chemically stable and easily processable polyolefin resin as a resin material used for coating an electric wire or the like has been studied. Yes. For example, in patent document 1, it mix | blends in the ratio of 2 to 20 mass parts with the polyolefin resin, the calcium carbonate particle | grains mix | blended in the ratio of 30 to 160 mass parts with respect to 100 mass parts of polyolefin resin. A flame retardant resin composition containing a silicone compound and a carboxylic acid metal salt blended at a ratio of 2 parts by mass or more and 15 parts by mass or less is disclosed.

JP-A-9-169918

  The flame retardant resin composition of Patent Document 1 ensures excellent mechanical properties and flame retardancy. However, the flame retardant resin composition of Patent Document 1 described above cannot be said to have sufficient characteristics for use as a cable jacket. In particular, the hardness to withstand external damage and impact, the easy tearability to easily tear the outer shell for terminal processing, and the low temperature embrittlement characteristics to suppress the crack from being generated at low temperatures are not sufficient. There wasn't.

  The present invention has been made in view of the above circumstances, and has a high hardness, a flame retardant resin composition capable of ensuring excellent flame retardancy while ensuring easy tearability and low temperature embrittlement characteristics, and uses the same. An object of the present invention is to provide a cable and an optical fiber cable.

  The inventors of the present invention have made various studies to solve the above problems, and have found that the above problems can be solved by combining not only a polyolefin resin but also an elastomer and an acid-modified resin. Thus, the present inventors have completed the present invention.

  That is, the present invention is a high-density polyethylene 55 mass% to 80 mass%, styrene elastomer 5 mass% to 30 mass%, polypropylene elastomer 5 mass% to 15 mass%, and acid-modified polyolefin compound 5 mass% or more. Calcium carbonate particles blended at a ratio of 20 parts by weight or more and 50 parts by weight or less and silicone system blended at a ratio of 1 part by weight or more and 10 parts by weight or less with respect to 100 parts by weight of the base resin including 20% by weight or less. It is a flame retardant resin composition containing a compound and a fatty acid-containing compound blended at a ratio of 2 parts by mass or more and 20 parts by mass or less.

  According to the flame-retardant resin composition of the present invention, the hardness is high, and excellent flame retardancy can be ensured while ensuring easy tearability and low-temperature embrittlement characteristics.

  In addition, the present inventors inferred the reason why the flame retardant resin composition of the present invention has high hardness, easy tearability, low temperature embrittlement characteristics and excellent flame retardancy as follows. Yes.

  That is, by setting the high density polyethylene in the base resin at the above-described ratio, the flame retardant resin composition can have high hardness and excellent impact resistance. However, high-density polyethylene has a high crystallinity and lowers the compatibility of the base resin with calcium carbonate particles, so that the low-temperature embrittlement characteristics are deteriorated. Therefore, by adjusting the ratio of the styrene elastomer and the acid-modified polyolefin compound in the base resin to the above-mentioned ratio, the crystallinity of the base resin can be lowered, so that the compatibility with calcium carbonate particles is improved, and the low-temperature embrittlement characteristics are improved. Can be improved.

  In addition, by setting the polypropylene-based elastomer in the above-described proportion in the base resin, the interface between the polypropylene-based elastomer and the high-density polyethylene becomes a starting point when tearing, and easy tearability can be improved. However, since the polypropylene elastomer is inferior in low-temperature embrittlement characteristics, the low-temperature embrittlement characteristics of the base resin are deteriorated. Therefore, the low temperature embrittlement characteristics can be improved by setting the styrene elastomer and the acid-modified polyolefin compound in the base resin in the above-described proportions.

  Furthermore, by containing calcium carbonate in the base resin in the above-mentioned proportion, it acts as a flame retardant, and also serves as a starting point for tearing the interface between calcium carbonate and high-density polyethylene, thereby improving easy tearability. it can.

In the flame retardant resin composition, the high density polyethylene preferably has a density of 945 kg / m ³ or more.

  In this case, superior hardness can be obtained as compared with the case where the density of the high-density polyethylene is out of the above range.

  In the flame retardant resin composition, the acid-modified polyolefin compound is preferably a maleic anhydride-modified ethylene-α olefin copolymer.

  In this case, superior low temperature embrittlement characteristics can be obtained as compared with the case where the acid-modified polyolefin compound is not maleic anhydride-modified polyethylene.

  In the flame retardant resin composition, the fatty acid-containing compound is preferably magnesium stearate or calcium stearate.

  In this case, more excellent flame retardancy can be obtained as compared with the case where the fatty acid-containing compound is neither magnesium stearate nor calcium stearate.

  In the flame retardant resin composition, the silicone compound is preferably a silicone gum.

  In this case, bloom is less likely to occur than when the silicone compound is not silicone gum.

  This invention is equipped with the insulated wire which has a conductor and the insulating layer which coat | covers the said conductor, and the said insulating layer is a cable comprised with the flame-retardant resin composition mentioned above.

  The present invention is a cable having a conductor, an insulating layer covering the conductor, and a sheath covering the insulating layer, wherein at least one of the insulating layer and the sheath is composed of the above-mentioned flame-retardant resin composition. Cable.

  The present invention is an optical fiber cable having an optical fiber and a sheath covering the optical fiber, wherein the sheath is composed of the above-mentioned flame retardant resin composition.

  According to the present invention, there are provided a flame retardant resin composition having high hardness, easy tearability and low temperature embrittlement characteristics, and excellent flame retardancy, and a cable and an optical fiber cable using the same. The

It is a partial side view which shows one Embodiment of the cable of this invention. It is sectional drawing along the II-II line of FIG. It is sectional drawing which shows one Embodiment of the optical fiber of this invention. It is sectional drawing which shows the optical fiber sample for easy tearability measurement.

  Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS.

[cable]
FIG. 1 is a partial side view showing an embodiment of a cable according to the present invention, and FIG. 2 is a cross-sectional view taken along line II-II in FIG. As shown in FIGS. 1 and 2, the cable 10 includes one insulated wire 4 and a sheath 3 that covers the one insulated wire 4. The insulated wire 4 includes an inner conductor 1 and an insulating layer 2 that covers the inner conductor 1.

  Here, the insulating layer 2 and the sheath 3 are made of a flame retardant resin composition, and the flame retardant resin composition has a high density polyethylene of 55% by mass to 80% by mass and a styrene elastomer of 5% by mass or more. 30 to 50 parts by mass with respect to 100 parts by mass of base resin including 30% by mass or less, polypropylene elastomer 5 to 15% by mass, and acid-modified polyolefin compound 5 to 20% by mass. Including calcium carbonate particles blended in proportion, a silicone compound blended in a proportion of 1 to 10 parts by weight, and a fatty acid-containing compound blended in a proportion of 2 to 20 parts by weight Yes.

  The flame-retardant resin composition has high hardness, and can ensure excellent flame retardancy while ensuring easy tearability and low-temperature embrittlement characteristics.

[Cable manufacturing method]
Next, a method for manufacturing the cable 10 described above will be described.

(conductor)
First, the inner conductor 1 is prepared. The inner conductor 1 may be composed of only one strand, or may be configured by bundling a plurality of strands. Further, the inner conductor 1 is not particularly limited with respect to the conductor diameter, the material of the conductor, and the like, and can be appropriately determined according to the application.

(Flame retardant resin composition)
Next, the flame retardant resin composition is prepared. As described above, the flame retardant resin composition is high density polyethylene 55% by mass to 80% by mass, styrene elastomer 5% by mass to 30% by mass, polypropylene elastomer 5% by mass to 15% by mass, and Calcium carbonate particles blended in a ratio of 20 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the base resin containing 5% by mass or more and 20% by mass or less of the acid-modified polyolefin compound, and 1 part by mass or more and 10 parts by mass or less. And a fatty acid-containing compound compounded at a ratio of 2 parts by mass or more and 20 parts by mass or less.

(High density polyethylene)
High density polyethylene, it is preferable density of 942kg / ^{m 3} or more 970 kg / ^{m 3} or less. More preferably still density of 945 kg / ^{m 3} or more, and still more preferably 950 kg / ^{m 3} or more.

When the density of the high density polyethylene is less than 942 kg / m ³ , the hardness of the flame retardant resin composition is significantly reduced. On the other hand, when the density is larger than 970 kg / m ³ , the low-temperature embrittlement characteristics are remarkably deteriorated.

  As described above, the high density polyethylene has a ratio of 55% by mass to 80% by mass in the base resin. When the proportion of the high density polyethylene is less than 55% by mass, the hardness of the flame retardant resin composition is significantly reduced. Moreover, when a ratio is larger than 80 mass%, a low temperature embrittlement characteristic will fall remarkably.

(Styrene elastomer)
The styrene elastomer is not particularly limited and can be appropriately selected and used. For example, polystyrene-poly (ethylene / propylene) block copolymer (SEP), styrene-isoprene-styrene block copolymer (SIS), styrene-butadiene-styrene block copolymer (SBS), styrene-butadiene-butylene- Styrene block copolymer (SBBS) and hydrogenated products thereof, styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-ethylene-butylene-ethylene block copolymer (SEBC), etc. Of these, one or more of them can be used as appropriate. Among these, styrene-ethylene-butylene-styrene block copolymer (SEBS) is particularly preferable because it exhibits an excellent effect in improving the low-temperature embrittlement characteristics.

  As described above, the styrene-based elastomer has a ratio of 5% by mass to 30% by mass in the base resin. When the ratio of the styrene elastomer is less than 5% by mass, the low temperature embrittlement characteristics of the flame retardant resin composition are significantly lowered. On the other hand, when the ratio is larger than 30% by mass, the hardness is remarkably lowered.

The styrene elastomer preferably has a density of 910 kg / m ³ or more and 940 kg / m ³ or less. In this case, when the density of the styrene elastomer is out of the above range, the hardness of the flame retardant resin composition is significantly reduced when the density is less than 910 kg / m 3. Moreover, when larger than 940 kg / m <3>, a low temperature embrittlement characteristic will fall remarkably.

(Polypropylene elastomer)
It does not specifically limit as a polypropylene-type elastomer, It can select suitably and can be used. For example, a copolymer obtained by copolymerizing propylene with an α-olefin component such as ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene and the like.

  As described above, the polypropylene-based elastomer has a ratio of 5% by mass to 15% by mass in the base resin. When the ratio of a polypropylene-type elastomer is less than 5 mass%, the easy tear property of a flame-retardant resin composition falls remarkably. Moreover, when a ratio is larger than 15 mass%, a low temperature embrittlement characteristic will fall remarkably. Furthermore, the blending ratio of the polypropylene-based elastomer is preferably 10% by mass or less. In this case, the low temperature embrittlement characteristics can be improved.

(Acid-modified polyolefin compound)
The acid-modified polyolefin compound is not particularly limited and can be appropriately selected and used. Examples thereof include carboxylic acids such as maleic anhydride, acrylic acid, and methacrylic acid or carboxylic acid anhydrides, or unsaturated organic acids such as esters thereof and esters thereof, and a partial copolymer of polyolefin. Specific examples of the acid-modified polyolefin compound include maleic anhydride-modified polyethylene, maleic anhydride-modified polypropylene, maleic anhydride-modified ethylene-α olefin copolymer, maleic anhydride-modified styrene elastomer, maleic anhydride-modified ethylene-propylene copolymer. A polymer etc. are mentioned. Among these, a maleic anhydride-modified ethylene-α-olefin copolymer is particularly preferable because it exhibits an excellent effect in improving the low-temperature embrittlement characteristics.

  As described above, the acid-modified polyolefin compound has a ratio of 5% by mass or more and 20% by mass or less in the base resin. When the blending ratio of the acid-modified polyolefin compound is less than 5% by mass, the low-temperature embrittlement characteristics of the flame retardant resin composition are significantly lowered. Moreover, when a mixture ratio is larger than 20 mass%, hardness will fall notably.

  The base resin may contain other resins in addition to high-density polyethylene, styrene-based elastomer, polypropylene-based elastomer, and acid-modified polyolefin compound. Examples of such other resins include ethylene-acetic acid. Vinyl copolymer resin (EVA), ethylene-ethyl acrylate copolymer (EEA), polyethylene (PE), etc. are mentioned. The ratio of these other resins in the base resin is preferably 15% by mass or less, more preferably 8% by mass or less, and further preferably 3% by mass or less.

(Calcium carbonate particles)
The calcium carbonate particles may be either heavy calcium carbonate or light calcium carbonate, but heavy calcium carbonate is preferred because it is readily available and inexpensive. The average particle diameter of the calcium carbonate particles is preferably 0.7 μm or more, more preferably 1.0 μm or more, and further preferably 1.5 μm or more. If the average particle size of the calcium carbonate particles is too small, the flame retardancy may be reduced. In addition, if the average particle size of the calcium carbonate particles is too large, the low-temperature embrittlement characteristics may be lowered. Therefore, the upper limit of the average particle size of the calcium carbonate particles is preferably 3.6 μm or less, more preferably It is 2.2 μm or less.

In the present invention, the “average particle size” means that the area S of the two-dimensional image when a plurality of calcium carbonate particles are observed with an SEM is obtained, and these areas S are considered to be equal to the area of a circle, respectively. From these areas, the following formula:
R = 2 × (S / π) 1/2
The average value of R calculated based on

  As described above, the calcium carbonate particles are blended in an amount of 20 to 50 parts by mass with respect to 100 parts by mass of the base resin. When the blending ratio of the calcium carbonate particles is less than 20 parts by mass, the easy tearability and flame retardancy of the flame retardant resin composition are significantly reduced. Moreover, when a mixture ratio is larger than 50 mass parts, a low temperature embrittlement characteristic will fall remarkably.

(Silicone compound)
The silicone-based compound functions as a flame retardant aid, and examples thereof include polyorganosiloxane. Here, the polyorganosiloxane has a siloxane bond as a main chain and an organic group in a side chain, and examples of the organic group include a methyl group, a vinyl group, an ethyl group, a propyl group, and a phenyl group. Specific examples of the polyorganosiloxane include dimethylpolysiloxane, methylethylpolysiloxane, methyloctylpolysiloxane, methylvinylpolysiloxane, methylphenylpolysiloxane, methyl (3,3,3-trifluoropropyl) polysiloxane, and the like. Is mentioned. Examples of the polyorganosiloxane include silicone powder, silicone gum, and silicone resin. Among these, silicone gum is preferable. In this case, bloom is less likely to occur.

  As described above, the silicone compound is blended at a ratio of 1 part by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the base resin. When the ratio of the silicone compound to 100 parts by mass of the base resin is less than 1 part by mass, the flame retardancy is significantly reduced. Moreover, when the compounding ratio of the silicone compound with respect to 100 parts by mass of the base resin is larger than 10 parts by mass, bleeding out of the silicone compound at the time of extrusion of the flame retardant resin composition cannot be sufficiently suppressed.

  The silicone compound is preferably blended at a ratio of 1 part by mass or more and 3 parts by mass or less with respect to 100 parts by mass of the base resin. In this case, more excellent hardness can be obtained as compared with the case where the blending ratio of the silicone compound with respect to 100 parts by mass of the base resin is out of the above range.

  The silicone compound may be previously attached to the surface of calcium carbonate. In this case, it is preferable that the entire calcium carbonate contained in the flame retardant resin composition is coated with a silicone compound. In this case, since the calcium carbonate can be easily dispersed in the polyolefin resin, the uniformity of characteristics in the flame retardant resin composition is further improved. Moreover, the bleed-out of the silicone compound at the time of extrusion of the flame retardant resin composition can be more sufficiently suppressed.

  As a method for attaching the silicone compound to the surface of calcium carbonate, for example, a silicone compound is added to calcium carbonate and mixed to obtain a mixture, and then the mixture is dried at 40 to 75 ° C. for 10 to 40 minutes. The dried mixture can be obtained by grinding with a Henschel mixer, an atomizer or the like.

(Fatty acid-containing compound)
The fatty acid-containing compound functions as a flame retardant aid. The fatty acid-containing compound is a fatty acid or a metal salt thereof. Here, as the fatty acid, for example, a fatty acid having 12 to 28 carbon atoms is used. Examples of such fatty acids include lauric acid, myristic acid, palmitic acid, stearic acid, tuberculostearic acid, oleic acid, linoleic acid, arachidonic acid, behenic acid and montanic acid. Among these, as the fatty acid, stearic acid or tuberculostearic acid is preferable, and stearic acid is particularly preferable. In this case, more excellent flame retardancy can be obtained as compared with the case of using a fatty acid other than stearic acid or tuberculostearic acid.

  Examples of the metal constituting the fatty acid metal salt include magnesium, calcium, zinc and lead. As the fatty acid metal salt, magnesium stearate or calcium stearate is preferable. In this case, more excellent flame retardancy can be obtained as compared with the case where the fatty acid-containing compound is neither magnesium stearate nor calcium stearate.

  As described above, the fatty acid-containing compound is blended at a ratio of 2 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the base resin. When the blending ratio of the fatty acid-containing compound is less than 2 parts by mass, flame retardancy is significantly reduced. Moreover, when the mixture ratio of a fatty acid containing compound is larger than 20 mass parts, the bleed-out of the fatty acid containing compound at the time of extrusion processing of a flame-retardant resin composition cannot fully be suppressed.

  The fatty acid-containing compound is preferably blended at a ratio of 5 parts by mass or less. In this case, superior hardness can be obtained as compared with the case where the proportion of the fatty acid-containing compound is larger than 5 parts by mass.

  The flame retardant resin composition may further include a filler such as an antioxidant, an ultraviolet deterioration inhibitor, a processing aid, a color pigment, a lubricant, and carbon black as necessary. For example, the antioxidant is preferably contained in an amount of 0.1 parts by mass or more and 2 parts by mass or less with respect to 100 parts by mass of the base resin. In this case, excellent heat aging characteristics can be obtained.

  The flame retardant resin composition can be obtained by kneading high density polyethylene, styrene elastomer, polypropylene elastomer, acid-modified polyolefin compound, calcium carbonate particles, silicone compound, fatty acid-containing compound and the like. The kneading can be performed with a kneading machine such as a Banbury mixer, a tumbler, a pressure kneader, a kneading extruder, a twin screw extruder, a mixing roll, and the like. At this time, from the viewpoint of improving the dispersibility of the silicone compound, a part of the base resin and the silicone compound are kneaded, and the obtained master batch (MB) is mixed with the remaining base resin, calcium carbonate, and fatty acid. You may knead | mix with a compound etc.

  Next, the inner conductor 1 is covered with the flame retardant resin composition. Specifically, the flame retardant resin composition is melt kneaded using an extruder to form a tubular extrudate. Then, the tubular extrudate is continuously coated on the inner conductor 1. Thus, the insulated wire 4 is obtained.

(sheath)
Finally, one insulated wire 4 obtained as described above is prepared, and these insulated wires 4 are covered with the sheath 3 produced using the above-mentioned flame-retardant resin composition. The sheath 3 protects the insulating layer 2 from physical or chemical damage.

  The cable 10 is obtained as described above.

  The present invention is not limited to the above embodiment. For example, in the above embodiment, the cable 10 has one insulated wire 4, but the cable of the present invention is not limited to a cable having one insulated wire 4, and the insulated wire is provided inside the sheath 3. Two or more 4 may be included.

  Moreover, in the said embodiment, although the insulating layer 2 and the sheath 3 of the insulated wire 4 are comprised with said flame-retardant resin composition, the insulating layer 2 is comprised with normal insulating resin, and only the sheath 3 is the said. The flame retardant resin composition may be used.

[Optical fiber cable]
FIG. 3 is a sectional view showing an indoor type optical fiber cable as an embodiment of the optical fiber cable according to the present invention. As shown in FIG. 3, the indoor optical fiber cable 20 includes one optical fiber 11, two tension members 12, and a sheath 13 that covers the optical fiber 11 and the tension member 12. The tension member is made of a material having a high tensile tension such as a steel wire.

  Here, the sheath 13 is composed of a flame retardant resin composition, and the flame retardant resin composition is 55% by mass to 80% by mass of high-density polyethylene, and 5% by mass to 30% by mass of a styrene elastomer. , Based on 100 parts by mass of the base resin containing 5% by mass to 15% by mass of the polypropylene elastomer and 5% by mass to 20% by mass of the acid-modified polyolefin compound. Calcium carbonate particles, a silicone compound compounded at a ratio of 1 to 10 parts by mass, and a fatty acid-containing compound compounded at a ratio of 2 to 20 parts by mass.

  The flame-retardant resin composition has high hardness, and can ensure excellent flame retardancy while ensuring easy tearability and low-temperature embrittlement characteristics.

[Manufacturing method of optical fiber cable]
Furthermore, the manufacturing method of the said optical fiber cable 20 is demonstrated.

  First, the optical fiber 11, the tension member 12, and the flame retardant resin composition are prepared.

  Next, the optical fiber 11 and the tension member 12 are coated with the flame retardant resin composition. Specifically, the flame retardant resin composition is melt-kneaded using an extruder. Then, the cylindrical extrudate having the cross-sectional shape shown in FIG. 3 is extruded from the extruder onto the optical fiber 11 and the tension member 12 arranged as shown in FIG. 11 and the tension member 12 are continuously coated. Thus, the optical fiber cable 20 is obtained.

  The present invention is not limited to the above embodiment. That is, the optical fiber cable is not limited to the indoor type optical fiber cable, and any type of cable may be used as long as the flame retardant resin composition is applicable.

  Hereinafter, the content of the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to the following examples.

(Examples 1-16 and Comparative Examples 1-8)
Base resin, calcium carbonate, silicone masterbatch (silicone MB), fatty acid-containing compound, antioxidant masterbatch (antioxidant MB) are blended in the blending amounts shown in Tables 1 to 3, and at 160 ° C by a Banbury mixer. The mixture was kneaded for 15 minutes to obtain a flame retardant resin composition. In addition, in Tables 1-3, the unit of the compounding quantity of each compounding component is a mass part. In Tables 1 to 3, the blending amount of high-density polyethylene, styrene-based elastomer, polypropylene-based elastomer, and acid-modified polyolefin compound is not 100 parts by mass. However, silicone MB and antioxidant MB also contain resin. If the resin in silicone MB and antioxidant MB is added to high density polyethylene, styrene elastomer, polypropylene elastomer, and acid-modified polyolefin compound, the total amount of base resin is 100 parts by mass.

Specifically, the following were used as the base resin, calcium carbonate, silicone MB, fatty acid-containing compound, and antioxidant MB.
(1) Base resin (A) High density polyethylene (HDPE) (trade name “Novatec HD HD322W”, manufactured by Nippon Polyethylene Co., Ltd., density 951 kg / m ³ )
(B) Styrenic elastomer (B-1) Styrene-ethylene-butylene-ethylene block copolymer (SEBC) (trade name “DYNARON 4600P”, manufactured by JSR, density 910 kg / m ³ )
(B-2) Styrene-butadiene-butylene-styrene block copolymer (SBBS1) (trade name “Tuftec P-1500”, manufactured by Asahi Kasei Chemicals Corporation, density 940 kg / m ³ )
(B-3) Styrene-butadiene-butylene-styrene block copolymer (SBBS2) (trade name “Tuftec P-3000”, manufactured by Asahi Kasei Chemicals Corporation, density 940 kg / m ³ )
(C) Polypropylene elastomer (PP elastomer) (trade name “Toughmer XM5070”, manufactured by Mitsui Chemicals, Inc.)
(D) Acid-modified polyolefin compound (acid-modified PO) (trade name “Toughmer MA8510”, manufactured by Mitsui Chemicals, Inc.)
(2) Calcium carbonate particles (A) (Ca1 carbonate) (trade name “NCC-P”, manufactured by Nitto Flour Chemical Co., Ltd., average particle size 1.7 μm)
(B) (Ca2 carbonate) (trade name “NCC-P # 2300”, manufactured by Nitto Flour Chemical Co., Ltd., average particle size 1.0 μm)
(3) Silicone compound (silicone MB) (trade name “X-22-2125H”, manufactured by Shin-Etsu Chemical Co., Ltd., containing 50 mass% silicone gum and 50 mass% PE)
(4) Fatty acid-containing compound (Mg stearate) (trade name “Efcochem MGS”, manufactured by ADEKA)
(5) Antioxidant (Antioxidant MB) (trade name “C-174 / 2A”, manufactured by Dainichi Seika Kogyo Co., Ltd., containing 50 mass% antioxidant and 50 mass% EVA)

  The obtained flame retardant resin composition was kneaded at 160 ° C. for 15 minutes with a Banbury mixer. Thereafter, the flame-retardant resin composition was molded using a mold to obtain a sheet-like molded body having a thickness of 2 mm.

The obtained flame retardant resin composition was kneaded at 160 ° C. for 15 minutes with a Banbury mixer. Thereafter, the flame retardant resin composition is put into a single screw extruder (L / D = 20, screw shape: full flight screw, manufactured by Mars Seiki Co., Ltd.), and a tube-like extrudate is extruded from the extruder. A coated electric wire sample was obtained by coating a flame retardant resin composition on a single wire / cross-sectional area of 2 mm ² ) with a thickness of 0.7 mm.

  The obtained flame retardant resin composition was kneaded at 160 ° C. for 15 minutes with a Banbury mixer. Thereafter, the flame retardant resin composition was put into a single-screw extruder (L / D = 20, screw shape: full flight screw, manufactured by Mars Seiki Co., Ltd.), and from the extruder, a cylinder having a cross-sectional shape shown in FIG. The flame retardant resin composition has a shape in which one core of the optical fiber has a short diameter of 1.6 mm, a long diameter of 2.0 mm, and a distance between the notch for tearing and the optical fiber of 0.4 mm by extruding a shaped extrudate. An optical fiber cable sample was obtained by covering with an object.

  About the flame retardant resin composition of the above-mentioned Examples 1-16 and Comparative Examples 1-8, evaluation about hardness, easy tear property, low temperature embrittlement property, and flame retardance was performed as follows.

<Hardness>
A sample having a size of 20 mm in length and 50 mm in width was prepared from the sheet-like molded body having a thickness of 2 mm, and the Shore D hardness was measured with a durometer (type D) in accordance with JIS K7215. In the measurement, the number of measurements was 5, and an average of five measurement results was adopted as a measurement value. In this example, the shore D hardness was 50 or more, which was regarded as acceptable.

<Easy tearability>
Using the above-described optical fiber cable sample, the notch of the jacket of the optical fiber cable sample was previously torn to several centimeters, and both the torn ends were fixed with a chuck, and the tensile speed was 500 mm / min. At 200 mm, the tearing force was measured. In the measurement, the number of measurements was 5, and an average of five measurement results was adopted as a measurement value. In the present Example, it was set as the pass by tearing force 12N or less.

<Low temperature embrittlement characteristics>
A sample having a size of 6 mm in length and 38 mm in width was produced from the sheet-like molded body having a thickness of 2 mm and subjected to an impact resistance test at a low temperature in accordance with JIS C3005. Specifically, the impact resistance test was performed in increments of 0 ° C. to 5 ° C., and the lowest temperature at which no cracks occurred on the sheet surface after the impact was applied was defined as the embrittlement temperature. In this example, the embrittlement temperature was −30 ° C. or lower, and the test was accepted.

<Flame retardance>
The above covered wire sample was subjected to a 60 ° inclined combustion test in accordance with JIS K3005. In addition, the 60 ° inclined combustion test is performed on 10 coated electric wire samples, and the sample whose fire extinguishing time (unit: second) is within 60 seconds is regarded as acceptable, and the acceptance rate of 10 coated electric wire samples is calculated. The average value of the fire extinguishing time was determined, and this was defined as the 60 ° inclined combustion time. The fire extinguishing time is the time from immediately after the end of flame contact (immediately after separating the burner flame from the electric wire) to self-extinguishing, and the shorter the fire extinguishing time, the higher the flame retardancy. At this time, the flame contact was performed until ignition occurred in the coated wire sample within 30 seconds. In this example, an acceptance rate of 100% was considered acceptable.

  From the results shown in Tables 1 to 3, the flame retardant resin compositions of Examples 1 to 16 reached the acceptance criteria in terms of hardness, easy tearability, low temperature embrittlement characteristics, and flame retardancy. On the other hand, the flame retardant resin compositions of Comparative Examples 1 to 8 did not reach the acceptance criteria in at least one of hardness, easy tearability, low temperature embrittlement characteristics, and flame retardancy.

  From this, it was confirmed that according to the flame retardant resin composition of the present invention, the hardness is high, and excellent flame retardancy can be ensured while ensuring easy tearability and low temperature embrittlement characteristics.

DESCRIPTION OF SYMBOLS 1 ... Internal conductor 2 ... Insulating layer 3 ... Sheath 4 ... Insulated electric wire 10 ... Cable 11 ... Optical fiber 12 ... Tension member 13 ... Sheath 20 ... Optical fiber cable

Claims (8)

High density polyethylene 55 mass% or more and 80 mass% or less,
5% by mass to 30% by mass of a styrene elastomer,
With respect to 100 parts by mass of the base resin including 5% by mass to 15% by mass of the polypropylene elastomer and 5% by mass to 20% by mass of the acid-modified polyolefin compound,
Calcium carbonate particles blended at a ratio of 20 parts by mass or more and 50 parts by mass or less;
A silicone compound compounded in a proportion of 1 part by mass or more and 10 parts by mass or less;
A flame retardant resin composition comprising a fatty acid-containing compound blended at a ratio of 2 parts by mass or more and 20 parts by mass or less. The flame-retardant resin composition according to claim 1, wherein the density of the high-density polyethylene is 945 kg / m ³ or more.   The flame retardant resin composition according to claim 1, wherein the acid-modified polyolefin compound is a maleic anhydride-modified ethylene-α-olefin copolymer.   The flame retardant resin composition according to any one of claims 1 to 3, wherein the fatty acid-containing compound is magnesium stearate or calcium stearate.   The flame retardant resin composition according to any one of claims 1 to 4, wherein the silicone compound is silicone gum. Conductors,
An insulated wire having an insulating layer covering the conductor;
The cable with which the said insulating layer is comprised with the flame-retardant resin composition as described in any one of Claims 1-5. Conductors,
An insulating layer covering the conductor;
A cable having a sheath covering the insulating layer,
A cable in which at least one of the insulating layer and the sheath is composed of the flame-retardant resin composition according to any one of claims 1 to 5. Optical fiber,
An optical fiber cable having a sheath covering the optical fiber,
An optical fiber cable in which the sheath is composed of the flame retardant resin composition according to any one of claims 1 to 5.

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