JP2016222875A - Elastomer composition and cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an elastomer composition having properties required for a sheath material of a cab tire cable such as oil resistance and excellent in processability, toughness and low temperature property during extrusion and a cable using the same for the sheath material.SOLUTION: There is provided an elastomer composition containing: a base polymer constituted by chlorinated polyethylene and polyolefin and having a mass ratio of the chlorinated polyethylene and the polyolefin of 50:50 to 80:20, where a melting point, Shore A hardness and melt flow rate of the polyolefin are 85°C or less, 50 or more and 0.5 g/10 min. or more, respectively; carbon; and peroxide in an aspect of the invention.SELECTED DRAWING: None

Description

  The present invention relates to an elastomer composition and a cable manufactured using the same.

  Generally, a resin composition is used as a material for a sheath that is a covering layer in a cable. The kind of the resin composition used as such a sheath material differs depending on the use of the electric wire or cable.

  For example, a sheath material of a cabtire cable used for a movable part such as a harbor crane is required to have flexibility, bending resistance, wear resistance, oil resistance, weather resistance, and the like. Therefore, conventionally, blended compositions such as chloroprene rubber and chlorinated polyethylene have been used as materials satisfying these characteristics (for example, Patent Document 1).

  When the cabtire cable is used in a mine in a cold region, a movable part in a freezer, or the like, it is required to cope with an extremely low temperature such as −50 ° C. or less. When used under such extremely low temperature conditions, chloroprene rubber has insufficient low temperature characteristics, and chlorinated polyethylene is preferably used as the sheath material. The embrittlement temperature of chloroprene rubber is about −40 ° C., whereas chlorinated polyethylene has an embrittlement temperature of −60 ° C. or less depending on the grade, and is particularly excellent in low temperature properties.

JP 2013-41794 A

  Many commercially available chlorinated polyethylenes have a high viscosity, and the extrusion processability is poor. Therefore, it is necessary to reduce the viscosity by adding a plasticizer. However, due to the low viscosity, toughness (tensile strength, tensile elongation, modulus) is reduced, and some of the specifications may not satisfy the characteristics. Therefore, reinforcing fillers such as carbon and surface-treated clay Needs to be added in large quantities. If it does so, a viscosity will increase eventually and low temperature characteristic will deteriorate in addition. Due to the above trade-offs, it has been difficult to achieve both workability, toughness and low temperature characteristics.

  Therefore, the present invention has properties required for a sheath material of a cabtire cable such as oil resistance, and in addition, an elastomer composition excellent in processability during extrusion, toughness, and low-temperature characteristics, and the sheath material The purpose is to provide a cable used in the above.

  One embodiment of the present invention provides the following elastomer compositions [1] to [6] in order to achieve the above object. Moreover, the other aspect of the present invention provides the following cable [7].

[1] It is composed of chlorinated polyethylene and polyolefin, the mass ratio of the chlorinated polyethylene to the polyolefin is 50:50 to 80:20, and the melting point, Shore A hardness, and melt flow rate of the polyolefin are each 85 ° C. or less. An elastomer composition comprising a base polymer of 50 or more and 0.5 g / 10 minutes or more, carbon, and a peroxide.

[2] The elastomer composition according to [1], wherein a tensile strength residual ratio and a tensile elongation residual ratio after immersion in IRM902 oil at 121 ° C. for 18 hours are both 60% or more.

[3] The elastomer composition according to [1] or [2], wherein a minimum Mooney viscosity (ML _{1 + 4} ) at 130 ° C. in a non-crosslinked state is 50 or less.

[4] The elastomer composition according to any one of [1] to [3], wherein the polyolefin is an ethylene / vinyl acetate copolymer containing 15% by mass or more of vinyl acetate.

[5] Any of the above [1] to [4], wherein an ethylene / vinyl acetate copolymer containing 15% by mass or more of vinyl acetate and an ethylene / glycidyl methacrylate copolymer are used in combination as the polyolefin. 2. The elastomer composition according to item 1.

[6] The elastomer composition according to any one of [1] to [5], wherein the 200% modulus is 4.8 MPa or more.

[7] An insulated wire and a sheath covering the periphery of the insulated wire, and the outermost layer of the sheath is made of the elastomer composition according to any one of [1] to [6]. cable.

  According to the present invention, an elastomer composition having properties required for a sheath material of a cabtyre cable such as oil resistance, in addition, excellent in processability during extrusion, toughness, and low-temperature characteristics, and the sheath material. It is possible to provide a cable used in the above.

FIG. 1 is a radial cross-sectional view of a cable according to a second embodiment. FIG. 2 is a radial cross-sectional view of the cable according to the third embodiment.

[First Embodiment]
(Elastomer composition)
The base polymer of the elastomer composition according to the first embodiment of the present invention is composed of chlorinated polyethylene (A) and polyolefin (B). The elastomer composition contains carbon and a peroxide as a crosslinking agent. The content of the base polymer in the elastomer composition is preferably 33 to 90% by mass, and more preferably 50 to 75% by mass.

  The mass ratio of chlorinated polyethylene (A) and polyolefin (B) in this base polymer (mass of chlorinated polyethylene (A): mass of polyolefin (B)) is 50:50 to 80:20. When the value of the mass ratio (mass of chlorinated polyethylene (A) / mass of polyolefin (B)) is larger than 80/20, the elastomer composition becomes highly viscous and the extrudability deteriorates. On the other hand, when the mass ratio is smaller than 50/50, the oil resistance of the elastomer composition is insufficient.

  The melting point, Shore A hardness, and melt flow rate of the polyolefin (B) in this base polymer are 85 ° C. or lower, 50 or higher, and 0.5 g / 10 min or higher, respectively.

The elastomer composition preferably has a tensile strength residual ratio and a tensile elongation residual ratio of 60% or more when immersed in IRM902 oil under the conditions of 121 ° C. and 18 hours. Further, the minimum Mooney viscosity (ML _{1 + 4} ) at 130 ° C. in a non-crosslinked state is preferably 50 or less. Here, “ML _{1 + 4} ” indicates a minimum Mooney viscosity obtained by a test performed using a L-shaped rotor under conditions of a preheating time of 1 minute and a rotation time of 4 minutes. Further, “minimum Mooney viscosity” represents the minimum value of Mooney viscosity obtained during the test.

  The elastomer composition preferably has a 200% modulus of 4.8 MPa or more. Here, the modulus is a value obtained by dividing the tensile force when a predetermined elongation is given to the test piece by the initial cross-sectional area of the test piece, and the 200% modulus is when the test piece is given 200% elongation. Is the value obtained by dividing the tensile force by the initial cross-sectional area of the test piece.

(Chlorinated polyethylene (A))
The chlorinated polyethylene (A) is preferably amorphous, and the heat of fusion due to melting of the residual crystals measured by differential scanning calorimetry (DSC) is preferably less than 2 J / g. Moreover, it is preferable that the chlorine content of chlorinated polyethylene (A) is 30% or more. In general, the melting point of chlorinated polyethylene is often higher than 120 ° C., and extrusion molding of an elastomer composition containing chlorinated polyethylene must be carried out at a temperature equal to or higher than the melting point. At this time, when the amount of chlorine in the chlorinated polyethylene is small and crystals remain, a cross-linking reaction occurs in the chlorinated polyethylene (A) and the polyolefin (B) to be blended in the extruder, and the molded product after extrusion. Appearance defects such as crusted skin and soot occur on the surface of the skin.

The minimum Mooney viscosity (ML _{1 + 4} ) at 121 ° C. of the chlorinated polyethylene (A) raw rubber (not crosslinked) is preferably 100 or less. If it is greater than 100, there may be a problem with the extrusion appearance.

(Polyolefin (B))
The polyolefin (B) is a copolymer of ethylene and other monomers, and examples of the other monomers include ethylene, propylene, butene, hexene, octene, vinyl acetate, ethyl acrylate, methyl acrylate, and glycidyl ethacrylate. In addition, you may use another polyolefin in the range in which the objective of this invention is achieved.

  In particular, the polyolefin (B) is preferably an ethylene / vinyl acetate copolymer containing 15% by mass or more of vinyl acetate. Alternatively, as the polyolefin (B), an ethylene / vinyl acetate copolymer containing 15% by mass or more of vinyl acetate and an ethylene / glycidyl methacrylate copolymer are preferably used in combination.

  As described above, the melting point of the polyolefin (B) needs to be 85 ° C. or lower. When the melting point is higher than 85 ° C., the extrusion of the elastomer composition containing the polyolefin (B) needs to be performed at a temperature higher than the temperature at which a crosslinking reaction occurs in the polyolefin (B). Due to the cross-linking, appearance defects such as wrinkles and lips occur on the surface of the molded product after extrusion. Moreover, it is preferable that melting | fusing point of polyolefin (B) is 75 degrees C or less.

  Further, the Shore A hardness of the polyolefin (B) needs to be 50 or more. When the Shore A hardness is lower than 50, the toughness (modulus) is insufficient. Further, the Shore A hardness of the polyolefin (B) is preferably 70 or more.

  Moreover, the melt flow rate of polyolefin (B) needs to be 0.5 g / 10 min or more. When the melt flow rate is lower than 0.5 g / 10 min, the viscosity of the elastomer composition containing the polyolefin (B) increases, and the extrusion moldability deteriorates. Moreover, it is preferable that the melt flow rate of polyolefin (B) is 1 g / 10min or more.

  The polyolefin (B) is preferably an ethylene / vinyl acetate copolymer from the viewpoint of compatibility with chlorinated polyethylene and processability of the elastomer composition. In this case, the copolymerization amount of vinyl acetate is preferably 15% by mass or more. This is because, when the copolymerization amount of vinyl acetate is smaller than 15% by mass, the melting point may exceed 85 ° C., the polarity is small, and the oil resistance is lowered.

  Further, it is more preferable that an ethylene / vinyl acetate copolymer containing 15% by mass or more of vinyl acetate and an ethylene / glycidyl methacrylate copolymer are used in combination as the polyolefin (B). In this case, the toughness such as tensile strength and 200% modulus of the elastomer composition can be improved. The reason for this is not known in detail, but is probably because the ethylene / glycidyl methacrylate copolymer serves as a compatibilizing agent in the blend of chlorinated polyethylene and ethylene / vinyl acetate copolymer. The ethylene / glycidyl methacrylate copolymer may contain a third component such as vinyl acetate or methyl acrylate.

(carbon)
The types of carbon contained in the elastomer composition according to the present embodiment are, for example, MT (Medium Thermal), FT (Fine Thermal), FEF (Fast Extruding Furnace), MAF (Medium abrasion furnace), HAF (High Abrasion Furnace). ). In addition, you may use another carbon in the range in which the objective of this invention is achieved. The carbon content in the elastomer composition is preferably 10 to 50 parts by mass, and more preferably 20 to 40 parts by mass.

(Peroxide)
Examples of the peroxide contained in the elastomer composition according to the present embodiment include dicumyl peroxide, 1,1-bis (tert-butylperoxy) cyclohexane, tert-butylperoxy 2-ethylhexyl carbonate, 4, 4-di-tert-butylperoxyvaleric acid n-butyl ester, bis (tert-butyldioxyisopropyl) benzene, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane. In addition, you may use another peroxide in the range in which the objective of this invention is achieved. The content of the peroxide in the elastomer composition is preferably 1 to 3 parts by mass, and more preferably 1.5 to 2.5 parts by mass.

(Other additives)
In addition to the above additives, the elastomer composition according to the present embodiment is appropriately filled with a filler, a crosslinking aid, a stabilizer, a lubricant, an antioxidant, a flame retardant, and the like, within the range where the object of the present invention is achieved. A plasticizer or the like may be included.

[Second Embodiment]
The second embodiment is a form of a cable having a single-layer sheath and using the elastomer composition according to the first embodiment as a material for the sheath.

(Cable configuration)
FIG. 1 is a sectional view in the radial direction of a cable 10 according to a second embodiment. The cable 10 includes an insulated wire 11 and a sheath 14 that covers the periphery of the insulated wire 11.

  The insulated wire 11 has a conductor 12 and an insulating layer 13 that covers the periphery of the conductor 12. The material of the conductor 12 and the insulating layer 13 is not specifically limited, Each can be formed using a known material. In the example shown in FIG. 1, three twisted insulated wires 11 are included in the cable 10, but the number of insulated wires 11 is not limited to a specific number.

  The sheath 14 is made of the elastomer composition according to the first embodiment and is cross-linked by heating, electron beam irradiation, or the like. For this reason, the sheath 14 is excellent in toughness and low temperature characteristics.

  The cable 10 may have other members such as a separator, a braid, and a shield tape made of metal foil as necessary.

[Third Embodiment]
The third embodiment is a form of a cable having a two-layer sheath and using the elastomer composition according to the first embodiment as a material of the outermost layer of the sheath.

(Cable configuration)
FIG. 2 is a radial sectional view of the cable 20 according to the third embodiment. The cable 20 includes an insulated wire 21, an inner layer sheath 26 that covers the periphery of the insulated wire 21, and an outer layer sheath 27 that covers the periphery of the inner layer sheath 26.

  The insulated wire 21 includes a conductor 22, an internal semiconductor layer 23 covering the periphery of the conductor 22, an insulating layer 24 covering the periphery of the internal semiconductor layer 23, and an external semiconductor layer 25 covering the periphery of the insulating layer 24. The materials of the conductor 22, the inner semiconductor layer 23, the insulating layer 24, and the outer semiconductor layer 25 are not particularly limited, and can be formed using known materials. In the example shown in FIG. 2, three twisted insulated wires 21 are included in the cable 10, but the number of insulated wires 21 is not limited to a specific number.

  The outer layer sheath 27 is composed of the elastomer composition according to the first embodiment and is crosslinked by heating, electron beam irradiation, or the like. For this reason, the outer layer sheath 27 is excellent in toughness and low temperature characteristics. On the other hand, the material of the inner layer sheath 26 is not particularly limited, and can be formed using a known material. The inner layer sheath 26 may have a multilayer structure.

  The cable 20 may have other members such as a separator, a braid, and a shield tape made of metal foil as necessary.

  In addition, since the insulated wire 21 has the internal semiconductor layer 23 and the external semiconductor layer 25, the cable 20 can be used as a high voltage cable, but the insulated wire 11 according to the second embodiment is used instead of the insulated wire 21. May be.

(Effect of embodiment)
According to the first to third embodiments, it is possible to provide an elastomer composition that is excellent in processability during extrusion, toughness, and low-temperature characteristics, and using the elastomer composition, A cable having a sheath excellent in low temperature characteristics can be provided.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited thereto.

  The cable 10 having the structure shown in FIG. 1 was manufactured by the following method and evaluated. In this example, 13 types of cables 10 having different contents of the elastomer composition as the material of the sheath 14 were manufactured.

  Among these 13 types of cables 10, the standard (the mass ratio of the chlorinated polyethylene (A) and the polyolefin (B) shown in the first embodiment is 50:50 to 80:20, and the polyolefin (A) Melting point, Shore A hardness, and melt flow rate are 85 ° C. or less, 50 or more, and 0.5 g / 10 min or more), 8 types satisfying Examples 1-8, and 5 types not satisfying Comparative Examples 1-5 To do.

  The upper part of Table 1 shows a blend (unit: part by mass) of an elastomer composition that is a material of the sheath 14 of Examples 1 to 8 and Comparative Examples 1 to 5. Table 2 also shows chlorinated polyethylene (A), ethylene / vinyl acetate copolymer (B1 to B4), ethylene / propylene copolymer (B5), and ethylene / glycidyl methacrylate copolymer as polyolefin (B). The detail of a polymer (B6) is shown.

Here, “Mooney viscosity” in Table 2 represents the minimum Mooney viscosity (ML _{1 + 4} ) at 130 ° C., “MFR” represents the melt flow rate, and “chlorine amount” represents the chlorine content in the chlorinated polyethylene (A). "VA amount" represents the mass percent concentration of vinyl acetate in the ethylene / vinyl acetate copolymer (B1 to B4), and "ethylene amount" represents the ethylene / propylene copolymer (B5). It represents the mass% concentration of ethylene, and “melting point: none” represents that it has no melting point because it is amorphous.

(Production of elastomer composition)
The elastomer composition shown in Table 1 was produced by the following method. First, a compound other than peroxide was charged into a kneader maintained at 80 ° C., and melt kneaded while raising the temperature to 160 ° C. Thereafter, the kneaded compound was put into a short-shaft extruder, extruded into a strand shape, passed through a pelletizer, and molded into a pellet shape. And this was injected | thrown-in to the blender hold | maintained at 40 degreeC, the peroxide was thrown in, and it impregnated with the peroxide, stirring, and obtained the elastomer composition.

(Manufacture of cables)
A sheath 14 having an outer diameter of 20 mm was extrusion coated onto three insulated wires 11 (cross-sectional area 14 mm ^{2 of} conductor 12 and thickness 0.80 mm of insulating layer 13) twisted in advance using a 115 mm extruder. In this case, the set temperatures of the cylinder, head, and die of the extruder were all 95 ° C. The cable 10 according to Examples 1 to 8 and Comparative Examples 1 to 5 was obtained by retaining the cable 10 with the sheath 14 being extrusion-coated in a steam pipe having a vapor pressure of 1.3 MPa for 2 minutes to crosslink the elastomer composition of the sheath 14. Got.

(Evaluation of elastomer composition)
The following tests and evaluations were performed on the sheath 14 of the cable 10 according to Examples 1 to 8 and Comparative Examples 1 to 5 and the elastomer composition before extrusion molding.

(1) Tensile test: Evaluation of mechanical properties (toughness) The sheath 14 is peeled off from each cable 10 and a tensile test is performed by a method in accordance with CSA-C22.2 No. 2556-07. Elongation, 200% modulus was evaluated. The tensile strength was 16.5 MPa or more, the tensile elongation was 300% or more, and the 200% modulus was 4.8 MPa or more.

(2) Embrittlement test: Evaluation of low temperature characteristics The sheath 14 was peeled off from each cable 10 and the embrittlement temperature was measured by a method based on JIS K 6261. An embrittlement temperature lower than −50 ° C. was accepted.

(3) Heat aging test: evaluation of heat resistance The sheath 14 was peeled off from each cable 10 and a heat aging test was performed by a method based on CSA-C22.2 No. 2556-07. The tensile strength residual rate and the tensile elongation residual rate after heat treatment at 100 ° C. for 168 h were evaluated, and both passed 50% or more.

(4) Oil resistance test: Evaluation of oil resistance The sheath 14 was peeled off from each cable 10 and an oil resistance test was performed by a method in accordance with CSA-C22.2 No. 2556-07. The tensile strength residual ratio and the tensile elongation residual ratio after being immersed in IRM902 oil under the conditions of 121 ° C. and 18 h were evaluated, and both passed 60% or more.

(5) Mooney viscosity measurement: Evaluation of extrusion processability
The minimum Mooney viscosity (ML _{1 + 4} ) of the elastomer composition before extrusion molding, that is, before crosslinking, was measured by a method based on JIS K 6300-1. A sample having a minimum Mooney viscosity (ML _{1 + 4} ) at 130 ° C. of 50 or less was regarded as acceptable.

(Evaluation of cable)
The following tests and evaluations were performed on the cables 10 according to Examples 1 to 8 and Comparative Examples 1 to 5.

(1) Observation of extrusion appearance: evaluation of extrusion processability The surface of the manufactured cable 10 was visually confirmed to confirm whether there were any abnormalities in appearance such as scabs or flaws.

  The result of each evaluation is shown in the latter part of Table 1.

  The cable 10 according to Examples 1 to 8 in which the blending content of the elastomer composition satisfies the standards shown in the first embodiment has all of mechanical characteristics, heat resistance, oil resistance, toughness, low temperature characteristics, and extrusion processability. Was a pass.

  On the other hand, about the cable 10 which concerns on the comparative example 1, the tensile strength residual rate of the elastomer composition after being immersed in oil was low, and oil resistance was disqualified. This is considered to be because the value of the mass ratio of the chlorinated polyethylene (A) and the polyolefin (B) (the mass of the chlorinated polyethylene (A) / the mass of the polyolefin (B)) is smaller than 50/50.

Moreover, about the cable 10 which concerns on the comparative example 2, the surface of the sheath 14 was a scabbard, and it failed the extrudability evaluation by observation of an extrusion external appearance. Moreover, the minimum Mooney viscosity (ML _{1 + 4} ) at 130 ° C. of the elastomer composition was larger than 50, and the evaluation of the extrudability by the Mooney viscosity measurement failed. This is presumably because the viscosity of the elastomer composition became too high because the value of the mass ratio of chlorinated polyethylene (A) and polyolefin (B) was greater than 80/20.

  Moreover, about the cable 10 which concerns on the comparative example 3, the surface of the sheath 14 was a scabbard, and it failed the extrusion workability evaluation by observation of an extrusion external appearance. This is considered to be because the melting point of the polyolefin (B) exceeds 85 ° C.

  Moreover, about the cable 10 which concerns on the comparative example 4, 200% modulus of the elastomer composition was smaller than 4.8 Mpa, and it failed to toughness evaluation. This is considered to be due to the Shore A hardness of the polyolefin (B) being less than 50.

Moreover, about the cable 10 which concerns on the comparative example 5, the surface of the sheath 14 was a scabbard, and it failed the extrusion workability evaluation by observation of an extrusion external appearance. Moreover, the minimum Mooney viscosity (ML _{1 + 4} ) at 130 ° C. of the elastomer composition was larger than 50, and the evaluation of the extrudability by the Mooney viscosity measurement failed. This is considered to be because the melt flow rate of the polyolefin (B) is smaller than 0.5 g / 10 minutes.

  From the above evaluation results, it was confirmed that the elastomer composition used for the cables 10 according to Examples 1 to 8 was excellent in processability during extrusion, toughness, and low temperature characteristics.

  Although the embodiments and examples of the present invention have been described above, the present invention is not limited to the above-described embodiments and examples, and various modifications can be made without departing from the spirit of the invention.

  The embodiments and examples described above do not limit the invention according to the claims. It should be noted that not all combinations of features described in the embodiments and examples are necessarily essential to the means for solving the problems of the invention.

10, 20 Cable 11, 21 Insulated wire 14 Sheath 26 Inner layer sheath 27 Outer layer sheath

Claims (7)

It is composed of chlorinated polyethylene and polyolefin, and the mass ratio of the chlorinated polyethylene and the polyolefin is 50:50 to 80:20, and the melting point, Shore A hardness, and melt flow rate of the polyolefin are 85 ° C. or less and 50 or more, respectively. A base polymer that is 0.5 g / 10 min or more;
Carbon,
With peroxide,
An elastomer composition comprising: The tensile strength residual ratio and the tensile elongation residual ratio after being immersed in IRM902 oil at 121 ° C. for 18 hours are both 60% or more.
The elastomer composition according to claim 1. The minimum Mooney viscosity (ML _{1 + 4} ) at 130 ° C. in an uncrosslinked state is 50 or less.
The elastomer composition according to claim 1 or 2. The polyolefin is an ethylene / vinyl acetate copolymer containing 15% by mass or more of vinyl acetate,
The elastomer composition according to any one of claims 1 to 3. As the polyolefin, an ethylene / vinyl acetate copolymer containing 15% by mass or more of vinyl acetate and an ethylene / glycidyl methacrylate copolymer were used in combination.
The elastomer composition according to any one of claims 1 to 4. 200% modulus is 4.8 MPa or more,
The elastomer composition according to any one of claims 1 to 5. Insulated wires,
A sheath covering the periphery of the insulated wire;
Have
The cable which the outermost layer of the said sheath consists of an elastomer composition of any one of Claims 1-6.

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