JP6243888B2 - Resin composition, electric wire and wire harness using the same - Google Patents

Description

  The present invention relates to a resin composition, an electric wire using the same, and a wire harness. Specifically, the present invention relates to a resin composition having high flexibility and an electric wire using the resin composition as a coating layer.

  An electric wire coating layer used in an engine room of an automobile or the like is required to have high-temperature meltability so that it does not melt even in a high-temperature environment. Conventionally, it has been proposed to use a thermoplastic resin such as polymethylpentene, which has a higher melting point than polyvinyl chloride or polypropylene resin, as the electric wire having high-temperature meltability.

  For example, in Patent Document 1, a metal hydrate, a hindered phenol antioxidant, a sulfur antioxidant and a metal are contained in a non-crosslinked base resin containing a propylene resin and a thermoplastic resin having a melting point of 180 ° C. or higher. A non-crosslinked flame retardant resin composition containing an oxide is disclosed. Patent Document 1 also discloses that the thermoplastic resin having a melting point of 180 ° C. or higher is polymethylpentene.

JP 2005-162931 A

  However, the resin composition described in Patent Document 1 has a problem that the flexibility of the propylene-based resin itself, which is a raw material, is low, and the flexibility becomes low when used as an electric wire.

  The present invention has been made in view of the problems of such conventional techniques. And the objective of this invention is providing the resin composition with a favorable softness | flexibility, and an electric wire using the same.

  The resin composition according to the first aspect of the present invention is a resin composition containing a polymethylpentene copolymer, a thermoplastic elastomer, and a flame retardant, and the flexural modulus of the resin composition is 400 MPa or less. is there.

  The resin composition according to the second aspect of the present invention relates to the resin composition of the first aspect, with respect to a total of 100 parts by mass of 30 to 60 parts by mass of a polymethylpentene copolymer and 40 to 70 parts by mass of a thermoplastic elastomer. And 8-30 parts by mass of a flame retardant.

  The resin composition according to the third aspect of the present invention relates to the resin composition of the first or second aspect, and the thermoplastic elastomer contains a crosslinked rubber component.

  The resin composition according to the fourth aspect of the present invention relates to the resin composition according to any one of the first to third aspects, and the flame retardant is a brominated flame retardant.

  The resin composition according to the fifth aspect of the present invention relates to the resin composition according to any one of the first to fourth aspects, wherein the flexural modulus of the polymethylpentene copolymer is 1400 MPa or less.

  The resin composition according to the sixth aspect of the present invention relates to the resin composition according to any one of the first to fifth aspects, wherein the thermoplastic elastomer has a type A durometer hardness of 50 or more.

  The electric wire which concerns on the 7th aspect of this invention is equipped with the coating layer which consists of a resin composition of any one of the 1st thru | or 6th aspect, and the conductor coat | covered with a coating layer.

  The wire harness which concerns on the 8th aspect of this invention is equipped with the electric wire of a 7th aspect.

  The resin composition of the present invention is a resin composition containing a polymethylpentene copolymer, a thermoplastic elastomer, and a flame retardant, and the flexural modulus of the resin composition is 400 MPa or less. Therefore, it becomes possible to provide a resin composition excellent in flexibility.

It is sectional drawing which shows the electric wire which concerns on embodiment of this invention. It is the schematic for demonstrating the measuring method of a softness | flexibility.

  Hereinafter, a resin composition and an electric wire according to an embodiment of the present invention will be described in detail with reference to the drawings. In addition, the dimension ratio of drawing is exaggerated on account of description, and may differ from an actual ratio.

[Resin composition]
The resin composition of this embodiment is a resin composition containing a polymethylpentene copolymer, a thermoplastic elastomer, and a flame retardant, and the flexural modulus of the resin composition is 400 MPa or less.

  Even when a non-crosslinked base resin containing a propylene-based resin and a thermoplastic resin such as polymethylpentene is used as in the prior art, it is possible to obtain a resin composition that satisfies high-temperature melt resistance. However, when such a resin composition is used as the base resin, it has been difficult to satisfy the requirements for flexibility required for wiring such as electric wires. Therefore, the resin composition of the present invention contains a polymethylpentene copolymer, a thermoplastic elastomer, and a flame retardant, thereby improving flexibility while improving heat resistance.

(Polymethylpentene copolymer)
As the polymethylpentene copolymer, a copolymer obtained by copolymerizing a methylpentene monomer and another α-olefin is used. The methylpentene monomer is preferably 4-methylpentene-1.

  The polymethylpentene copolymer is preferably contained in an amount of 30 to 60 parts by mass. When the polymethylpentene copolymer is 30 parts by mass or more, a resin composition having good high temperature melt resistance can be obtained. Further, when the polymethylpentene copolymer is 60 parts by mass or less, a resin composition having good flexibility can be obtained, and therefore, it can be suitably used for a coating layer of an electric wire. In addition, it is more preferable that a polymethylpentene copolymer is 35 mass parts-55 mass parts. When the content of the polymethylpentene copolymer is within such a range, a resin composition having further excellent high-temperature melt resistance and flexibility can be obtained.

  The flexural modulus of the polymethylpentene copolymer is preferably 1400 MPa or less. More specifically, the flexural modulus of the polymethylpentene copolymer is preferably 300 MPa to 1400 MPa. When the flexural modulus of the polymethylpentene copolymer is 300 MPa or more and 1400 MPa or less, a resin composition having good flexibility can be obtained, and therefore, it can be suitably used for a coating layer of an electric wire. The flexural modulus of the polymethylpentene copolymer is more preferably 400 MPa or more and 800 MPa or less. When the flexural modulus of the polymethylpentene copolymer is in such a range, a resin composition with even better flexibility can be obtained. The value of the flexural modulus is a 3.2 mm-thick injection molded piece of the resin composition, according to ASTM-D790, at a test speed of 1.3 mm / min in a 23 ° C. atmosphere, and a distance between fulcrums of 51 mm. It can be obtained by measuring.

(Thermoplastic elastomer)
The thermoplastic elastomer (TPE) of the present invention is a polymer that has the same properties as vulcanized rubber at the operating temperature as defined in JIS K6418, but can be molded or remolded at the same temperature as the thermoplastic resin. Or it consists of a polymer blend. As thermoplastic elastomer (TPE), amide thermoplastic elastomer (TPA), ester thermoplastic elastomer (TPC), olefin thermoplastic elastomer (TPO), styrene thermoplastic elastomer (TPS), urethane thermoplastic elastomer (TPU), crosslinked thermoplastic rubber (TPV), and other thermoplastic elastomers (TPZ) can be used. These thermoplastic elastomers may be used alone or in combination of two or more.

  As the thermoplastic elastomer, it is preferable to use an olefin-based thermoplastic elastomer (TPO) and a crosslinked thermoplastic rubber (TPV). When an olefinic thermoplastic elastomer (TPO) and a crosslinked thermoplastic rubber (TPV) are used, a resin composition having good flexibility and high-temperature melt resistance can be obtained. In addition, as the thermoplastic elastomer, it is more preferable to use a crosslinked thermoplastic rubber (TPV). When a thermoplastic rubber crosslinked body (TPV) is used, a resin composition having good oil resistance can be obtained.

  Olefin-based thermoplastic elastomers (TPO) consist of a blend of polyolefin and normal rubber, and the rubber phase of the blend has no or little cross-linking points.

  Examples of the polyolefin used for the olefinic thermoplastic elastomer (TPO) include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene and 1-decene. An α-olefin homopolymer or two or more types of copolymers can be used. Specifically, a polypropylene resin, a polyethylene resin, or the like can be used.

  Examples of the rubber used for the olefinic thermoplastic elastomer (TPO) include natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene copolymer rubber (SBR), and acrylonitrile-butadiene copolymer. Rubber (NBR), chloroprene rubber (CR), butyl rubber (IIR), ethylene-propylene rubber (EPM), ethylene-propylene-diene rubber (EPDM), and the like can be used. The rubber used for the olefinic thermoplastic elastomer (TPO) is particularly preferably at least one of ethylene-propylene rubber (EPM) and ethylene-propylene-diene rubber (EPDM).

  The crosslinked thermoplastic rubber (TPV) is a blend of a thermoplastic resin and a normal rubber, and this rubber is crosslinked by dynamic vulcanization in the blending or kneading process. As the thermoplastic elastomer of this embodiment, it is preferable to use a blend of a thermoplastic resin and a crosslinked rubber because a resin composition having good oil resistance can be obtained. However, this rubber is not necessarily crosslinked by dynamic vulcanization. There is no need to be. That is, it is preferable that the thermoplastic elastomer of this embodiment includes a crosslinked rubber component.

  Examples of the thermoplastic resin used for the crosslinked thermoplastic rubber (TPV) include amide resins, ester resins, olefin resins, styrene resins, and urethane resins.

  The rubber used for the thermoplastic rubber crosslinked body (TPV) is not particularly limited. For example, natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene copolymer rubber (SBR), Acrylonitrile-butadiene copolymer rubber (NBR), chloroprene rubber (CR), butyl rubber (IIR), ethylene-propylene rubber (EPM), ethylene-propylene-diene rubber (EPDM), and the like can be used. The rubber used for the crosslinked thermoplastic rubber (TPV) is particularly preferably at least one of ethylene-propylene rubber (EPM) and ethylene-propylene-diene rubber (EPDM).

  The thermoplastic elastomer is preferably contained in an amount of 40 to 70 parts by mass. When the thermoplastic elastomer is 40 parts by mass or more, a resin composition having good flexibility can be obtained. Moreover, when a thermoplastic elastomer is 70 mass parts or less, the resin composition with favorable high temperature melt resistance can be obtained. In addition, it is more preferable that a thermoplastic elastomer is 45 mass parts-65 mass parts. When the content of the thermoplastic elastomer is within such a range, a resin composition with even better flexibility and high temperature melt resistance can be obtained.

  The instantaneous value of the type A durometer hardness of the thermoplastic elastomer is preferably 50 or more. More specifically, the instantaneous value of the type A durometer hardness of the thermoplastic elastomer is preferably 50 or more and 100 or less. When the instantaneous value of the type A durometer hardness is 50 or more and 100 or less, the wear resistance of the resin composition is further improved and can be suitably used for a coating layer of an electric wire. The instantaneous value of type A durometer hardness is more preferably 70 or more and 90 or less. By being in this range, a resin composition having good flexibility can be obtained, and can be suitably used for a coating layer of an electric wire. The instantaneous value of type A durometer hardness can be measured according to JIS K7215.

(Flame retardants)
As the flame retardant, for example, an organic flame retardant or an inorganic flame retardant can be used. These flame retardants may be used alone or in combination of two or more. As organic flame retardants, for example, halogen flame retardants such as bromine flame retardants and chlorine flame retardants, phosphorous flame retardants such as phosphate esters, condensed phosphate esters, cyclic phosphorus compounds, red phosphorus, etc. Can do. As the inorganic flame retardant, a metal hydroxide, an antimony flame retardant, or the like can be used. The flame retardant is preferably an organic flame retardant, and more preferably a halogen flame retardant. Further, it is more preferable to use a brominated flame retardant as the flame retardant. By using such a flame retardant, a resin composition having good heat aging resistance can be obtained.

  Examples of brominated flame retardants include 1,2-bis (bromophenyl) ethane, 1,2-bis (pentabromophenyl) ethane, hexabromobenzene, ethylene bis-dibromonorbornane dicarboximide, and ethylene bis-tetrabromo. Phthalimide, tetrabromobisphenol S, tris (2,3-dibromopropyl-1) isocyanurate, hexabromocyclododecane (HBCD), octabromophenyl ether, tetrabromobisphenol A (TBA), TBA epoxy oligomer or polymer, TBA- Bis (2,3-dibromopropyl ether), decabromodiphenyl oxide, polydibromophenylene oxide, bis (tribromophenoxy) ethane, ethylene bis-pentabromobenzene, dibromoethyl-dibu Mocyclohexane, dibromoneopentyl glycol, tribromophenol, tribromophenol allyl ether, tetradecabromodiphenoxybenzene, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, 2,2-bis ( 4-hydroxyethoxy-3,5-dibromophenyl) propane, pentabromophenol, pentabromotoluene, pentabromodiphenyl oxide, hexabromodiphenyl ether, octabromodiphenyl ether, octabromodiphenyl oxide, dibromoneopentyl glycol tetracarbonate, bis ( Tribromophenyl) fumaramide, N-methylhexabromophenylamine and the like can be used. In addition, as a brominated flame retardant, it is preferable to use 1, 2-bis (pentabromophenyl) ethane. By using such a flame retardant, a resin composition having good flame retardancy can be obtained.

  It is preferable that the compounding quantity of a flame retardant contains 8-30 mass parts with respect to a total of 100 mass parts of a polymethylpentene copolymer and a thermoplastic elastomer. When the blending amount of the flame retardant is 8 parts by mass or more, a resin composition having good flame retardancy can be obtained. When the blending amount of the flame retardant is 30 parts by mass or less, a resin composition having good heat aging resistance can be obtained. In addition, it is further more preferable that the compounding quantity of a flame retardant shall be 10-20 mass parts with respect to a total of 100 mass parts of a polymethylpentene copolymer and a thermoplastic elastomer. By being in this range, it becomes possible to obtain a resin composition with better flame retardancy and heat aging resistance.

  In addition to the above essential components, various additives can be added to the resin composition of the present embodiment as long as the effects of the present embodiment are not hindered. Additives include antioxidants, metal deactivators, anti-aging agents, lubricants, fillers, reinforcing agents, UV absorbers, stabilizers, plasticizers, pigments, dyes, colorants, antistatic agents, foaming agents, etc. Is mentioned.

  Although the resin composition of this embodiment is prepared by melt-kneading the above-mentioned material, the method can use a well-known means. For example, after pre-blending using a high-speed mixing device such as a Henschel mixer, the resin composition is kneaded using a known kneader such as a Banbury mixer, kneader, roll mill, single screw extruder, twin screw extruder, etc. Can be obtained.

  In addition, in order to improve the heat resistance of the resin composition, the resin composition after mixing may be irradiated with radiation to perform crosslinking treatment of the resin composition. For irradiation, for example, γ rays or electron beams can be used as a radiation source. By irradiating the resin composition after mixing them, radicals are generated in the molecules, and these radicals couple with each other to form intermolecular crosslinks. As a result, the heat resistance of the resin composition can be improved.

  Thus, the resin composition of this embodiment contains a polymethylpentene copolymer, a thermoplastic elastomer, and a flame retardant, and the flexural modulus of the resin composition is 400 MPa or less. When the flexural modulus of the resin composition is 400 MPa or less, since the flexibility of the resin composition is excellent, it can be suitably used for an electric wire coating layer or the like.

[Electrical wire]
As shown in FIG. 1, the electric wire 1 according to the present embodiment includes a coating layer 3 made of the resin composition described above and a conductor 2 covered with the coating layer 3.

  As described above, since the resin composition of the present embodiment is excellent in flexibility, it is suitable for an electric wire covering layer. FIG. 1 shows an example of an electric wire using the resin composition of the present embodiment as a coating layer. The electric wire 1 is formed by covering the conductor 2 with the covering layer 3.

  As the conductor 2, a single wire constituted by one strand may be used, or a stranded wire constituted by twisting a plurality of strands may be used. A stranded wire is also a concentric stranded wire in which one or several strands are centered and the strands are concentrically twisted around it; a collective stranded wire in which a plurality of strands are twisted together in the same direction; Any composite stranded wire in which a plurality of aggregate stranded wires are twisted concentrically can be used.

  The diameter of the conductor 2 and the diameter of each strand constituting the conductor 2 are not particularly limited. Furthermore, the material of the conductor 2 is not particularly limited, and for example, general metals, conductive fibers, and conductive polymers can be used. In particular, as the material of the conductor 2, known conductive metal materials such as copper, copper alloy, aluminum, and aluminum alloy can be used. These conductive metal materials are particularly preferable because of their good flexibility and conductivity. The surface of the conductor 2 may be plated, for example, tin plating, silver plating, or nickel plating.

  As described above, the coating layer 3 in the electric wire 1 of the present embodiment is prepared by melt-kneading the resin composition, and known methods can be used. Furthermore, a known means can be used for the method of coating the conductor 2 with the coating layer 3. For example, the coating layer 3 can be formed by a general extrusion molding method. And as an extruder used by the extrusion method, a single screw extruder or a twin screw extruder can be used, for example, and a screw, breaker plate, crosshead, distributor, nipple and die can be used.

  The resin composition constituting the coating layer 3 is melted and kneaded by a screw, and a certain amount is supplied to the crosshead via the breaker plate. The molten resin composition flows onto the circumference of the nipple by a distributor and is extruded in a state of being coated on the outer circumference of the conductor by a die, whereby the coating layer 3 covering the outer circumference of the conductor 2 can be obtained. .

  Thus, in the electric wire of this embodiment, a coating layer can be formed by extrusion molding in the same manner as a general resin composition for electric wires. In addition, in order to improve the heat resistance of a coating layer, after forming a coating layer in the outer periphery of a conductor, you may irradiate a radiation and an electron beam, and may perform the crosslinking process of a resin composition. As a result, the heat resistance of the coating layer can be improved.

  In addition, regarding the processing method of the resin composition, a method for kneading the resin material, a method for coating the electric wire, and a method for crosslinking the resin material such as thermal crosslinking and electron beam crosslinking should be selected according to the purpose. There is no particular limitation. Therefore, the processing method can be variously modified within the scope of the gist of the present invention.

[Wire Harness]
The wire harness according to the present embodiment includes the above-described electric wire. Since the above-mentioned resin composition is excellent in flexibility, when an electric wire using such a resin composition is used as a wire harness, for example, it can be preferably used as a wire harness for an automobile.

  As described above, the resin composition of the present embodiment contains a polymethylpentene copolymer, a thermoplastic elastomer, and a flame retardant, and the flexural modulus of the resin composition is 400 MPa or less. Thus, since the resin composition of this embodiment is excellent in a softness | flexibility, it can be used suitably also for the coating layer and wire harness of an electric wire. In addition, such a resin composition can be used not only as an electric wire or a wire harness but also as a resin molded product at a site where flexibility is required.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited to these Examples.

[Sample Preparation of Examples and Comparative Examples]
<Preparation of resin composition>
First, by using a kneader, the following polymethylpentene copolymer, thermoplastic elastomer, flame retardant, and flame retardant aid were melt-kneaded in the blending amounts shown in Tables 1 and 2, and each of the examples and comparative examples. A resin composition was prepared.
(Polymethylpentene copolymer)
-TPX (registered trademark) MX002: manufactured by Mitsui Chemicals, Inc .: flexural modulus 480 MPa
-TPX (registered trademark) MX004: manufactured by Mitsui Chemicals, Inc .: flexural modulus 750 MPa
-TPX (registered trademark) RT18: manufactured by Mitsui Chemicals, Inc .: flexural modulus 1450 MPa
(Thermoplastic elastomer)
Miralastomer (registered trademark) 8030NS: Mitsui Chemicals, Inc .: Crosslinked thermoplastic rubber (TPV): Type A durometer hardness 88
Miralastomer (registered trademark) 5030 NS: manufactured by Mitsui Chemicals, Inc .: crosslinked thermoplastic rubber (TPV): type A durometer hardness 51
Miralastomer (registered trademark) 4010 NS: manufactured by Mitsui Chemicals, Inc .: crosslinked thermoplastic rubber (TPV): type A durometer hardness 46
Prime TPO (registered trademark) R110MP: Prime Polymer Co., Ltd .: Olefin-based thermoplastic elastomer (TPO): Type A durometer hardness 68
(Flame retardants)
SAYTEX (registered trademark) 8010: manufactured by Albemarle Corporation, 1,2-bis (2,3,4,5,6-pentabromophenyl) ethane Kisuma (registered trademark) 5AL: manufactured by Kyowa Chemical Industry Co., Ltd., stearic acid Treated magnesium hydroxide (flame retardant aid)
-PATOX (registered trademark) -M: manufactured by Nippon Seiko Co., Ltd., antimony trioxide

<Production of electric wire>
Extrusion molding was performed on a 3 mm ² copper conductor at a temperature of 250 ° C. using an extrusion coating apparatus for producing electric wires, and electric wires coated with the resin compositions of the examples and comparative examples were produced. In addition, it adjusted so that the outer diameter of the electric wire which put the coating resin layer might be set to 3.25 mm in the case of extrusion molding.

[Evaluation]
<Bending elastic modulus>
The value of flexural modulus was measured by using a resin composition as an injection-molded piece having a thickness of 3.2 mm and a test speed of 1.3 mm / min and an inter-fulcrum distance of 51 mm under an atmosphere of 23 ° C. according to ASTM-D790. . The case where the flexural modulus was 400 MPa or less was evaluated as “◯”, and the case where it exceeded 400 MPa was evaluated as “x”.

<Flexibility>
First, a test sample made of a covered electric wire was cut so as to have a length of 100 mm. Next, as shown in FIG. 2, the test sample 10 was placed on the rollers 11 arranged at intervals of 60 mm. Then, the center of the test sample was weighted from above at a speed of 100 mm / min, and the maximum load until the wire fell was measured using a force gauge. A case where the force gauge value was less than 7N was evaluated as “◯”, a case where the force gauge value was 7N or more and 8.5N or less was evaluated as “Δ”, and a case where the force gauge value exceeded 8.5N was evaluated as “X”.

<High temperature meltability>
Evaluation of the high temperature melting resistance was performed as follows. First, the test wire was wound around a mandrel having a diameter equal to the outer diameter of the test wire in each example so that no gap was formed, and heated in an environment of 200 ° C. for 30 minutes. Then, the test wire was unwound from the mandrel, and the presence or absence of the exposed conductor was visually examined. The test wire in which the conductor was not exposed after heating at 200 ° C. was evaluated as “◯”. In addition, the electric wire for a test by which exposure of the conductor was recognized after heating at 200 degreeC was evaluated as "x".

<Flame retardance>
About the resin composition of the said Example and comparative example, flame retardance evaluation was implemented with the following method. First, the covered electric wire using the resin composition of an Example and a comparative example was cut | disconnected to length 600mm or more, and the test sample was produced. Next, each test sample was fixed in a draft at an angle of 45 degrees. And after making the inner flame part of a Bunsen burner contact the part of 500 mm +/- 5mm from the upper end of a test sample for 30 second, the Bunsen burner was removed. Then, after removing the Bunsen burner from the test sample, all the flames of the coating resin layer disappeared within 70 seconds, and the coating resin layer was ignited and flame fluctuation did not occur was evaluated as “◯”. On the other hand, what continued burning for more than 70 seconds was evaluated as "x".

<Heat aging resistance>
For heat aging resistance, an electric wire having a length of 350 mm was heated at 180 ° C. for 300 hours. Then, the electric wire was taken out from the oven and wound around a mandrel 1.5 times the outer diameter of the electric wire. Then, a voltage of 1 kV was applied for 1 minute, and evaluation was made as “◯” if dielectric breakdown did not occur and “×” if dielectric breakdown occurred.

<Abrasion resistance>
Abrasion resistance was evaluated by tape abrasion. First, a 150 J garnet sandpaper was prepared in which conductive bands of 5 mm to 10 mm were attached perpendicularly to the edge of the sandpaper at intervals of 75 mm at maximum. Appropriate brackets were attached to the pivot arm so that the test sample was located on the unused portion of the sandpaper wear tape. The test sample was stretched without stretching, and a test sample having a length of 900 mm was horizontally installed. The wear tape is brought into contact with the test sample and a 1500 g weight is added to the wear tape. In this state, the wear tape was moved at a speed of (1500 ± 75) mm / min, and the length of the wear tape until the test sample was worn and the metal conductor contacted the wear tape was measured. Thereafter, the test sample was moved 50 mm, and the test sample was rotated 90 ° clockwise. This procedure was repeated for a total of four measurements. The case where the length until contact was 330 mm or more was evaluated as “◯”, and the case where it was less than 330 mm was evaluated as “x”.

<Oil resistance>
The oil resistance was evaluated as follows. First, a liquid in which 2,2,4-trimethylpentane and toluene were mixed at a ratio of 1: 1 was prepared. Next, after measuring the outer diameter of the test sample, the test sample was immersed in a liquid for 20 hours. After immersion, the test sample was taken out of the liquid, the liquid adhering to the surface was wiped off, and the external shape of the same part as before the immersion was measured. And the change rate (%) of the outer diameter after immersion with respect to the outer diameter before immersion in the liquid was calculated | required from the following formula | equation. The case where the change rate of the outer diameter after immersion with respect to the outer diameter before immersion in the liquid was 15% or less was evaluated as “◯”, and the case where it exceeded 15% was evaluated as “x”.
Rate of change (%) = (outer diameter after immersion−outer diameter before immersion) / (outer diameter before immersion) × 100

[Evaluation results]
As shown in Tables 1 to 3, the resin compositions of Examples 1 to 15 were superior in flexibility as compared with Comparative Example 1 because the flexural modulus of the resin composition was 400 MPa or less.

  As shown in Table 1 and Table 2, since the resin composition of Examples 1 to 7 has a resin composition ratio of the polymethylpentene copolymer and the thermoplastic elastomer within a predetermined range, compared with Example 8, Excellent high-temperature melt resistance.

  As shown in Tables 1 and 2, the resin compositions of Examples 1 to 7 contain a predetermined amount of flame retardant, so that compared to Examples 9 and 10, flame retardancy or heat aging resistance is achieved. It was excellent.

  As shown in Tables 1 and 3, the resin compositions of Examples 1 to 7 were excellent in oil resistance compared to Example 11 because the thermoplastic elastomer contained a crosslinked rubber component.

  As shown in Table 1 and Table 3, since the resin compositions of Examples 1 to 7 use brominated flame retardants instead of the metal hydroxide flame retardants used in Example 12, the flame retardants It was excellent in nature.

  As shown in Table 3, the resin composition of Example 13 has 60 parts by mass of a metal hydroxide flame retardant, and thus has improved flame retardancy compared to Example 12. The heat aging resistance is reduced. This shows that it is preferable to use a brominated flame retardant instead of the metal hydroxide flame retardant from the viewpoint of achieving both heat resistance and heat aging resistance.

  As shown in Tables 1 and 3, the resin compositions of Examples 1 to 7 were superior in flexibility compared to Example 14 because the flexural modulus of the polymethylpentene copolymer was 1400 MPa or less.

  As shown in Tables 1 and 3, the resin compositions of Examples 1 to 7 have an abrasion resistance as compared with Example 15 because the instantaneous value of the type A durometer hardness of the crosslinked elastomer is 50 or more. It was excellent.

  As mentioned above, although this invention was demonstrated by the Example, this invention is not limited to these, A various deformation | transformation is possible within the range of the summary of this invention.

1 electric wire 2 conductor 3 coating layer

Claims (8)

A resin composition comprising a polymethylpentene copolymer, a thermoplastic elastomer, and a flame retardant,
A resin composition, wherein the resin composition has a flexural modulus of 400 MPa or less.   The said flame retardant 8-30 mass parts is contained with respect to a total of 100 mass parts of the said polymethylpentene copolymer 30-60 mass parts and the said thermoplastic elastomer 40-70 mass parts. Resin composition.   The resin composition according to claim 1, wherein the thermoplastic elastomer contains a crosslinked rubber component.   The resin composition according to any one of claims 1 to 3, wherein the flame retardant is a brominated flame retardant.   The resin composition according to any one of claims 1 to 4, wherein the polymethylpentene copolymer has a flexural modulus of 1400 MPa or less.   The resin composition according to any one of claims 1 to 5, wherein the thermoplastic elastomer has a type A durometer hardness of 50 or more. A coating layer (3) comprising the resin composition according to any one of claims 1 to 6;
A conductor (2) covered by the covering layer;
An electric wire (1) comprising:   A wire harness comprising the electric wire according to claim 7.

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