JP6046100B2 - 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.

  As a flame retardant resin composition capable of securing excellent mechanical properties and excellent low temperature embrittlement properties while also ensuring excellent flame retardancy, it is used as a polyolefin resin and as a flame retardant, calcium carbonate having an average particle size of less than 1.2 μm. In addition, a flame retardant resin composition obtained by adding a silicone compound such as silicone oil or magnesium stearate as a flame retardant aid is known (see Patent Document 1 below).

JP 2014-28910 A

  The flame retardant resin composition described in Patent Document 1 has been required to have flame retardance enough to pass a 60-degree tilt test based on JIS C3005. However, the flame retardance of the grade which passes the vertical | longitudinal single line | wire test based on JIS C3665-1 severer than this may be calculated | required. In this case, if the average particle size of calcium carbonate, which is a flame retardant, is 1.2 μm or more, flame retardancy can be improved. However, when the average particle size of calcium carbonate is increased, there is a problem that the low temperature embrittlement characteristics of the flame retardant resin composition are lowered.

  For this reason, the flame-retardant resin composition which can ensure the outstanding flame retardance while ensuring the outstanding mechanical characteristic and ensuring the low-temperature embrittlement characteristic was calculated | required.

  The present invention has been made in view of the above circumstances, and is a flammable resin composition capable of ensuring excellent mechanical properties and ensuring excellent flame retardancy while ensuring excellent low-temperature embrittlement properties. And it aims at providing the cable using this, and an optical fiber cable.

  In order to solve the above-mentioned problems, the present inventors have conducted various studies. When the flame retardant resin composition described in Patent Document 1 is blended with a monoester compound of a polyhydric alcohol and a fatty acid at a predetermined ratio, The present inventors have found that even when the average particle size of calcium carbonate is 1.2 μm or more in order to improve flame retardancy, excellent low temperature embrittlement characteristics can be ensured. In addition, when blending a monoester compound of a polyhydric alcohol and a fatty acid, excellent flame retardancy can be ensured even if the blending amount of the silicone compound is reduced, and therefore the present inventors can also ensure excellent mechanical properties. Found. Thus, the present inventors have completed the present invention.

That is, the present invention is more than 1 part by mass with respect to 100 parts by mass of the polyolefin resin, calcium carbonate blended at a ratio of 5 parts by mass to 120 parts by mass with respect to 100 parts by mass of the polyolefin resin. A first flame retardant auxiliary compounded at a ratio of 10 parts by mass or less; a second flame retardant auxiliary compounded at a ratio of 3 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the polyolefin resin; Containing a polyhydric alcohol and a fatty acid monoester compound blended in a proportion of 0.5 parts by mass or more and less than 5 parts by mass with respect to 100 parts by mass of the polyolefin resin, and the average particle size of the calcium carbonate is 1.2 μm less than 8.0 .mu.m, the first a silicone-based compound is a flame retardant aid, Ri said second flame retardant agent is a fatty acid or fatty acid metal salts der, the multi A flame retardant resin composition in which a monoester compound of a monohydric alcohol and a fatty acid is pentaerythritol monostearate .

  According to the flame-retardant resin composition of the present invention, it is possible to ensure better flame retardancy while ensuring excellent mechanical properties and excellent low-temperature embrittlement properties.

  In addition, the present inventors speculate as follows about the reason why more excellent flame retardancy is obtained in the flame retardant resin composition of the present invention.

  That is, a surface barrier layer is formed at the time of combustion by using calcium carbonate particles, a silicone compound as a first flame retardant aid, and a fatty acid or fatty acid metal salt as a second flame retardant aid. At this time, if the surface barrier layer is dense and such a dense surface barrier layer is quickly formed, it is considered that the flame retardant effect is enhanced. In order for the dense surface barrier layer to be formed quickly, it is necessary to close the gaps between the particles of calcium carbonate or decomposition products constituting the surface barrier layer as quickly as possible. In that respect, when the average particle diameter of the calcium carbonate particles is as large as 1.2 μm or more as in the present invention, the specific surface area decreases, so that the gap between the calcium carbonate particles can be quickly closed. As a result, it is considered that the formation speed of the dense surface barrier layer is increased and the flame retardant effect is enhanced.

  Furthermore, the polyolefin resin is decomposed into a combustible gas at the time of combustion, and brings about an effect of promoting combustion. However, by adding a monoester compound of a polyhydric alcohol and a fatty acid, the polyolefin resin does not decompose during combustion, and exhibits the effect of reinforcing the above-mentioned surface barrier layer as a carbide. Thereby, it is thought that a flame-retardant effect increases further.

  In addition, the present inventors presume the reason why excellent low temperature embrittlement characteristics can be obtained in the flame retardant resin composition of the present invention as follows.

  That is, by adding a monoester compound of polyhydric alcohol and fatty acid to the flame retardant resin composition, the monoester compound of polyhydric alcohol and fatty acid enters between the interface between the calcium carbonate particles and the polyolefin resin, and enters the interface. It is considered that the low temperature embrittlement characteristics are improved because the stress concentration of the material is relaxed.

  Moreover, in the said flame retardant resin composition, it is preferable that the silicone type compound which is a said 1st flame retardant adjuvant is mix | blended in the ratio of less than 5 mass parts with respect to 100 mass parts of said polyolefin resins.

  In this case, more excellent mechanical properties can be obtained as compared with the case where the compounding amount of the silicone compound as the first flame retardant aid is larger than the above range with respect to 100 parts by mass of the polyolefin resin.

  In the flame retardant resin composition, the monoester compound of polyhydric alcohol and fatty acid is preferably pentaerythritol monostearate.

  In this case, superior low temperature embrittlement characteristics can be obtained as compared with the case where the monoester compound of polyhydric alcohol and fatty acid is not pentaerythritol monostearate.

  In the said flame-retardant resin composition, it is preferable that the fatty acid or fatty acid metal salt that is the second flame retardant aid is magnesium stearate or calcium stearate.

  In this case, more excellent flame retardancy can be obtained as compared with the case where the fatty acid or fatty acid metal salt as the second flame retardant aid is neither magnesium stearate nor calcium stearate.

  Moreover, 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.

  Furthermore, 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 the flame retardant resin composition described above. It is a configured cable.

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

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. From these areas, the following formula:
R = 2 × (S / π) ^1/2
The average value of R calculated based on

  ADVANTAGE OF THE INVENTION According to this invention, the flame retardant resin composition which can ensure the outstanding flame retardance while ensuring the outstanding mechanical characteristic and the outstanding low temperature embrittlement characteristic, and a cable using the same An optical fiber cable is also provided.

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.

  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.

[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 insulating layer 2 and the sheaths 3 and 13 are made of a flame retardant resin composition, and the flame retardant resin composition is 5 parts by mass or more and 120 parts by mass with respect to 100 parts by mass of the polyolefin resin and the polyolefin resin. Calcium carbonate blended at a ratio of less than or equal to parts by mass, and a silicone compound that is a first flame retardant aid blended at a ratio of greater than 1 part by weight and less than or equal to 10 parts by weight with respect to 100 parts by weight of the polyolefin resin; Fatty acid or fatty acid metal salt that is the second flame retardant aid blended at a ratio of 3 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the polyolefin resin, and 0.5 parts by mass with respect to 100 parts by mass of the polyolefin resin. Including a polyhydric alcohol and a monoester compound of a fatty acid blended at a ratio of 5 parts by mass or less, the average particle size of the calcium carbonate is 1.2 μm or more and less than 8.0 μm It is.

  The said flame-retardant resin composition can also ensure the outstanding flame retardance, ensuring the outstanding mechanical characteristic and ensuring the low-temperature embrittlement characteristic. For this reason, the insulating layer 2 and the sheaths 3 and 13 composed of the flame retardant resin composition can ensure excellent flame retardancy while ensuring excellent mechanical properties and excellent low temperature embrittlement properties. . For this reason, the cable 10 and the optical fiber cable 20 can ensure more excellent flame retardancy while ensuring excellent mechanical properties and excellent low-temperature embrittlement properties.

[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)
On the other hand, the flame retardant resin composition is prepared. As described above, the flame retardant resin composition is based on the polyolefin resin, calcium carbonate blended at a ratio of 5 parts by mass or more and 120 parts by mass or less with respect to 100 parts by mass of the polyolefin resin, and 100 parts by mass of the polyolefin resin. 1 part flame retardant and a silicone compound which is a first flame retardant aid blended at a ratio of 10 parts by mass or less and a ratio of 3 parts by mass to 20 parts by mass with respect to 100 parts by mass of the polyolefin resin. The fatty acid or fatty acid metal salt that is the second flame retardant aid and a monoester of polyhydric alcohol and fatty acid blended in a proportion of 0.5 parts by weight or more and less than 5 parts by weight with respect to 100 parts by weight of the polyolefin resin And an average particle diameter of the calcium carbonate is 1.2 μm or more and less than 8.0 μm.

(Polyolefin resin)
Examples of polyolefin resins include ethylene resins and propylene resins. You may use these individually by 1 type or in mixture of 2 or more types. Here, the ethylene-based resin refers to a resin containing ethylene as a structural unit. Examples of the ethylene-based resin include polyethylene resin (PE), ethylene ethyl acrylate copolymer (EEA), and ethylene vinyl acetate copolymer ( EVA) and the like. Moreover, as a propylene-type resin, the resin containing propylene as a structural unit is mentioned, for example, a polypropylene resin (PP) etc. are mentioned.

  Here, when the polyolefin resin is a polyethylene resin, it is preferable because more excellent flame retardancy can be obtained. Moreover, when it is set as an ethylene vinyl acetate copolymer or a polypropylene resin, since the more outstanding mechanical characteristic can be acquired, it is preferable.

(Calcium carbonate)
The calcium carbonate particles may be either heavy calcium carbonate or light calcium carbonate. As described above, the average particle size of the calcium carbonate particles is 1.2 μm or more and less than 8.0 μm. In this case, superior flame retardancy can be obtained as compared with the case where the average particle diameter of the calcium carbonate particles is less than 1.2 μm. On the other hand, the low temperature embrittlement characteristics are remarkably improved as compared with the case where the average particle diameter of the calcium carbonate particles is 8.0 μm or more.

  Calcium carbonate is blended at a ratio of 5 parts by mass or more and 120 parts by mass or less with respect to 100 parts by mass of the polyolefin resin. In this case, there is an advantage that mechanical properties are excellent as compared with the case where the blending ratio of calcium carbonate with respect to 100 parts by mass of the polyolefin resin is larger than 120 parts by mass. On the other hand, the flame retardance which was excellent compared with the case where the compounding ratio of calcium carbonate with respect to 100 mass parts of polyolefin resin is less than 5 mass parts can be obtained.

(First flame retardant aid)
Examples of the silicone compound that is the first flame retardant aid include polyorganosiloxane. Here, the polyorganosiloxane has a siloxane bond as a main chain and an organic group in a side chain. 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, and methyl (3,3,3-trifluoropropyl) polysiloxane. 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-based compound that is the first flame retardant aid is blended at a ratio of more than 1 part by mass and 10 parts by mass or less with respect to 100 parts by mass of the polyolefin resin. In this case, superior flame retardancy can be obtained as compared with the case where the blending ratio of the silicone compound to 100 parts by mass of the polyolefin resin is 1 part by mass or less. On the other hand, compared with the case where the compounding ratio of the silicone compound with respect to 100 parts by mass of the polyolefin resin is larger than 10 parts by mass, the bloom is less likely to occur.

  The silicone compound that is the first flame retardant aid is preferably blended at a ratio of less than 5 parts by mass with respect to 100 parts by mass of the polyolefin resin. In this case, more excellent mechanical characteristics can be obtained as compared with the case where the blending ratio of the silicone compound to 100 parts by mass of the polyolefin resin is 5 parts by mass or more.

  The silicone compound that is the first flame retardant aid may be previously attached to the surface of the 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 bleeding out of the silicone compound at the time of extrusion processing of the flame retardant resin composition can be 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.

(Second flame retardant aid)
Examples of the second flame retardant aid include fatty acids or metal salts of fatty acids. 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, lead and the like. As the fatty acid metal salt, magnesium stearate or calcium stearate is preferable. In this case, more excellent flame retardancy can be obtained.

  The fatty acid or fatty acid metal salt that is the second flame retardant aid is blended at a ratio of 3 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the polyolefin resin as described above.

  In this case, excellent flame retardancy can be obtained as compared with the case where the blending ratio of the fatty acid or the metal salt of the fatty acid as the second flame retardant auxiliary with respect to 100 parts by mass of the polyolefin resin is less than 3 parts by mass. On the other hand, compared to the case where the blending ratio of the fatty acid or the metal salt of the fatty acid with respect to 100 parts by mass of the polyolefin resin is larger than 20 parts by mass, the bloom is less likely to occur.

(Monoester compound of polyhydric alcohol and fatty acid)
The valence of the polyhydric alcohol may be 2 or more, but is preferably 4 to 10. Examples of the polyhydric alcohol include pentaerythritol, sorbitol, sorbitan, a condensed dimer or trimer thereof, and the like. These can be used alone or in combination of two or more.

  Examples of fatty acids include unsaturated fatty acids such as saturated fatty acids such as palmitic acid and higher saturated fatty acids such as stearic acid, saturated fatty acid diacids such as adipic acid, and unsaturated higher fatty acids such as oleic acid and erucic acid. Examples include saturated fatty acids. Here, “higher” generally means that the fatty acid has 6 or more carbon atoms. In particular, industrially 12 to 18 carbon atoms are suitable because they are easily available from the viewpoint of price and quantity. Further, as the saturated fatty acid, a saturated fatty acid having a melting point not higher than the processing temperature of the polyolefin resin is preferable.

  The monoester compound of polyhydric alcohol and fatty acid is blended at a ratio of 0.5 parts by mass or more and less than 5 parts by mass with respect to 100 parts by mass of the polyolefin resin.

  In this case, when the blending ratio of the monoester compound of polyhydric alcohol and fatty acid is within the above range, it is difficult compared to the blending ratio of the monoester compound of polyhydric alcohol and fatty acid being less than 0.5 parts by mass. The flammability is significantly improved. On the other hand, flame retardancy is remarkably improved as compared with the case where the blending ratio of the polyhydric alcohol and the monoester compound of fatty acid is 5 parts by mass or more.

  Examples of the monoester compound of polyhydric alcohol and fatty acid include pentaerythritol monostearate, sorbitan monostearate, dipentaerythritol adipate and the like, and pentaerythritol monostearate is particularly preferable. In this case, superior low-temperature embrittlement characteristics can be obtained as compared with the case where pentaerythritol monostearate is not used.

  The flame retardant resin composition may further contain a filler such as an antioxidant, an ultraviolet deterioration inhibitor, a processing aid, a color pigment, a lubricant, and carbon black as necessary.

  The flame retardant resin composition includes a polyolefin resin, calcium carbonate, a silicone compound as a first flame retardant aid, a fatty acid or a metal salt of a fatty acid as a second flame retardant aid, a monostearate of a polyhydric alcohol and a fatty acid. It can be obtained by kneading the rate. 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 polyolefin resin and the silicone compound are kneaded, and the obtained master batch (MB) is mixed with the remaining polyolefin resin, calcium carbonate, fatty acid or You may knead | mix with the metal salt of a fatty acid, the monoester compound of a polyhydric alcohol, and a fatty acid.

  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. A resin portion made of polypropylene or the like may be provided between the sheath 3 and the insulated wire 4.

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

[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 1-21 and Comparative Examples 1-11)
Polyolefin resin, calcium carbonate, silicone master batch (silicone MB) as the first flame retardant aid, magnesium stearate (Mg stearate) as the second flame retardant aid, and monoester compound of polyhydric alcohol and fatty acid, It mix | blended with the compounding quantity shown to Tables 1-6, and knead | mixed for 15 minutes at 160 degreeC with the Banbury mixer, and obtained the flame-retardant resin composition. In Tables 1 to 6, the unit of the blending amount of each blending component is part by mass. Moreover, in Tables 1-6, although the compounding quantity of polyolefin resin is not 100 mass parts, resin is contained also in silicone MB, If polyolefin resin and resin in silicone MB are totaled, polyolefin resin will be included. The total amount is 100 parts by mass.

Specific examples of the polyolefin resin, calcium carbonate, silicone MB, fatty acid or fatty acid metal salt, and monoester compound of polyhydric alcohol and fatty acid are as follows.
(1) Polyolefin resin (A) Polyethylene resin (PE) (trade name “Excellen GMH GH030”, manufactured by Sumitomo Chemical Co., Ltd.)
(B) Ethylene acrylate copolymer (EEA) (trade name “DPDJ-6503”, manufactured by Nihon Unicar)
(C) Ethylene vinyl acetate copolymer (EVA) (trade name “Evaflex V5274”, manufactured by Mitsui DuPont Polychemical Co., Ltd.)
(D) Polypropylene resin (PP) (trade name “E111G”, manufactured by Prime Polymer Co., Ltd.)
(2) Calcium carbonate (A) Calcium carbonate particles (average particle size 0.70 μm) (trade name “Softon 3200”, manufactured by Shiraishi Calcium Co., Ltd.)
(B) Calcium carbonate particles (average particle size 1.0 μm) (trade name “NCC P-2300”, manufactured by Nitto Flour & Chemical Co., Ltd.)
(C) Calcium carbonate particles (average particle size 1.2 μm) (trade name “NCC P-1000”, manufactured by Nitto Flour Chemical Co., Ltd.)
(D) Calcium carbonate particles (average particle size 1.7 μm) (trade name “NCC-P”, manufactured by Nitto Flour Chemical Co., Ltd.)
(E) Calcium carbonate particles (average particle size 2.2 μm) (trade name “Softon 1000”, manufactured by Shiraishi Calcium)
(F) Calcium carbonate particles (average particle size 3.6 μm) (trade name “BF100”, manufactured by Shiraishi Calcium Co., Ltd.)
(G) Calcium carbonate particles (average particle size 8.0 μm) (trade name “BF300”, manufactured by Shiroishi Calcium Co., Ltd.)
(3) First flame retardant aid (A) Silicone MB (trade name “X-22-2125H”, manufactured by Shin-Etsu Chemical Co., Ltd.)
(4) Second flame retardant aid (A) Magnesium stearate (Mg stearate) (trade name “Efcochem MGS”, manufactured by ADEKA)
(5) Monoester compound of polyhydric alcohol and fatty acid (A) Pentaerythritol monostearate (trade name “Exepal PE-MS, manufactured by Kao Corporation”)
(B) Dipentaerythritol adipic acid ester (trade name “Prene Riser ST-210”, manufactured by Ajinomoto Fine Techno Co., Ltd.)

Next, this flame retardant resin composition was kneaded at 160 ° C. for 15 minutes by 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 tubular extrudate is extruded from the extruder. A conductor (number of strands / cross-sectional area of 2 mm ² ) was coated to a thickness of 0.7 mm. Thus, an insulated wire was obtained.

  The insulated wires of Examples 1 to 21 and Comparative Examples 1 to 11 obtained as described above were evaluated for flame retardancy, mechanical properties, and low temperature embrittlement properties as follows.

<Flame retardance>
(60 degree inclined combustion test)
About the insulated wire of Examples 1-21 and Comparative Examples 1-11, the 60 degree inclination combustion test of JISK3005 was done and the flame retardance was evaluated. The results are shown in Tables 1-6. In Tables 1 to 6, for each example and comparative example, 10 insulated wires were prepared and a flame retardancy test was performed, and the average value of the fire extinguishing time (unit: seconds) of 10 insulated wires was measured. did. Here, the fire extinguishing time is the time from self-extinguishing immediately after the end of flame contact (immediately after releasing the burner flame from the electric wire), and the shorter the fire extinguishing time, the higher the flame retardancy. At this time, the flame contact was performed until ignition of the electric wire occurred within 30 seconds. The results are shown in Tables 1-6. In Tables 1 to 6, the unit of the average value of the fire extinguishing time is seconds, and the acceptance criteria for the average value of the fire extinguishing time are as follows.

60 seconds or less: Pass over 60 seconds: Fail

(90 degree combustion test)
Ten insulated wires of Examples 1 to 21 and Comparative Examples 1 to 11 were prepared, respectively, and a vertical single-flammability test was performed based on JIS C3665-1 to evaluate flame retardancy. At this time, specifically, if the length from the lower end of the upper support material that supports the insulated wire at the upper part to the end point of carbonization is 50 mm or more and 540 mm or less, it is considered “pass”, and in the case of less than 50 mm or more than 540 mm Was “failed”. And the pass rate (%) was calculated | required. The results are shown in Tables 1-6. In Tables 1 to 6, the combustion time is also shown. In Tables 1 to 6, the flame retardant pass / fail criteria were as follows. In the combustion test, a burner flame was contacted for 60 seconds.

Pass rate is 70% or more: Pass pass rate is less than 70%: Fail

<Mechanical properties>
The mechanical properties were evaluated based on the measured tensile strength of the insulated wires of Examples 1 to 21 and Comparative Examples 1 to 11, which were subjected to a tensile test according to JIS C3005. The results are shown in Tables 1-6. In Tables 1-6, the unit of tensile strength was MPa, and the pass / fail criteria for tensile strength were as follows. In the tensile test, the tensile speed was 200 mm / min, and the distance between the marked lines was 20 mm.

10 MPa or more: pass less than 10 MPa: fail

<Low temperature embrittlement characteristics>
The low temperature embrittlement characteristics were evaluated by conducting low temperature embrittlement tests based on JIS K7216 for the flame retardant resin compositions of Examples 1 to 21 and Comparative Examples 1 to 11. Specifically, using the flame retardant resin compositions of Examples 1 to 21 and Comparative Examples 1 to 11, sheet-like test pieces having a thickness of 2 mm were prepared, and each test piece was subjected to 0 ° C to- It was placed in a test tank maintained at a test temperature of 60 ° C., fixed to the tip of a cantilever, a predetermined impact (test speed 2 m / s) was given to the test piece, and the state of destruction of the test piece was observed. . The test was performed in increments of 5 ° C. from 0 ° C. to −60 ° C., and the low temperature resistance was evaluated at the temperature (crack generation temperature) at which the test piece was cracked by impact. The results are shown in Tables 1-6. The low temperature resistance is acceptable when the crack generation temperature is lower than −50 ° C., “O” in the pass / fail column in the table, and the crack generation temperature not lower than −50 ° C. “X” is described in the pass / fail column.

  From the results shown in Tables 1 to 6, the insulated wires of Examples 1 to 21 reached the acceptance criteria in terms of flame retardancy, mechanical properties, and low temperature resistance. On the other hand, the insulated wires of Comparative Examples 1 to 11 did not reach the acceptance criteria in at least one of flame retardancy, mechanical properties, and low temperature resistance.

  From this, it was confirmed that according to the flame retardant resin composition of the present invention, it was possible to ensure excellent mechanical properties and also ensure excellent flame retardancy while ensuring excellent low temperature resistance. .

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 (6)

A polyolefin resin;
Calcium carbonate blended at a ratio of 5 parts by mass or more and 120 parts by mass or less with respect to 100 parts by mass of the polyolefin resin,
A first flame retardant aid blended in a proportion of greater than 1 part by weight and less than or equal to 10 parts by weight with respect to 100 parts by weight of the polyolefin resin;
A second flame retardant auxiliary compounded in a proportion of 3 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the polyolefin resin;
Including a polyhydric alcohol and a monoester compound of a fatty acid blended in a proportion of 0.5 parts by mass or more and less than 5 parts by mass with respect to 100 parts by mass of the polyolefin resin,
The calcium carbonate particles have an average particle size of 1.2 μm or more and less than 8.0 μm, the first flame retardant assistant is a silicone compound, and the second flame retardant assistant is a fatty acid or a metal salt of a fatty acid. Oh it is,
A flame retardant resin composition, wherein the monoester compound of polyhydric alcohol and fatty acid is pentaerythritol monostearate .   The flame retardant resin composition according to claim 1, wherein the silicone compound as the first flame retardant aid is blended at a ratio of less than 5 parts by mass with respect to 100 parts by mass of the polyolefin resin.   The flame retardant resin composition according to claim 1 or 2, wherein the fatty acid or fatty acid metal salt as the second flame retardant aid is magnesium stearate or calcium stearate. 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 1-3 . Conductors,
An insulating layer covering the conductor;
A cable having a sheath covering the insulating layer,
The cable comprised by the flame-retardant resin composition as described in any one of Claims 1-3 in which at least one of the said insulating layer and the said sheath is. 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 3 .

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