JP2011241246A - Flame-retardant resin composition, insulated wire, wire harness, and cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flame-retardant resin composition that can improve flame retardancy and external damage resistance of an insulated wire, an insulated wire, a wire harness, and a cable.SOLUTION: The flame-retardant resin composition contains: a polyolefin resin including an ethylenic polymer containing an oxygen atom in the molecular skeleton; metal hydroxide particles; alkyl β-carboxy acrylate deposited on the surface of the metal hydroxide particle; and a polyorganosiloxane, wherein the metal hydroxide particle and the alkyl β-carboxy acrylate are contained at the ratio of 20-50 pts.mass based on 100 pts.mass of the polyolefin resin, and the polyorganosiloxane is contained at the ratio of 2-10 pts.mass based on 100 pts.mass of the polyolefin resin.

Description

  The present invention relates to a flame retardant resin composition, an insulated wire, a wire harness, and a cable.

  Polyvinyl chloride compositions are widely used in wire coatings, tubes, tapes, packaging materials, building materials, etc. because of their good electrical insulation and excellent flame retardancy and mechanical properties. Lead-free polyvinyl chloride resin that does not use lead as a stabilizer is becoming mainstream because of concerns about the effects on the human body.

  The lead-free polyvinyl chloride resin contains chlorine atoms in its molecular structure, and generates toxic and harmful chlorine gas during combustion. Therefore, a vinyl chloride electric wire replacement using a so-called eco-material with higher safety is being studied.

  Examples of such eco-materials include ethylene materials such as polyethylene (PE), ethylene vinyl acetate copolymer (EVA), and ethylene ethyl acrylate copolymer (EEA), polypropylene (PP), and ethylene propylene rubber ( EP rubbers) and those obtained by adding a large amount of metal hydroxides such as magnesium hydroxide and aluminum hydroxide based on a composite resin blended with polyolefin such as styrene elastomer (for example, Patent Document 1) are known. reference).

  In particular, the following Patent Document 2 discloses a flame retardant surface-treated with 100 parts by mass of a resin containing 30 parts by mass or more of isotactic polypropylene and atactic polypropylene of polyolefin, and 1 to 3% ethyl β-carboxyacrylate. It has been proposed to improve flame retardancy, electrical insulation, and trauma resistance by a resin composition containing 100 to 250 parts by mass and 0.1 to 0.5 parts by mass of physic peroxide.

Japanese Patent No. 3358228 JP 2009-40973 A

  However, the resin composition described in Patent Document 2 still has room for improvement in terms of trauma resistance and flame retardancy.

  This invention is made | formed in view of the said situation, and provides the flame-retardant resin composition, insulated wire, wire harness, and cable which can improve the flame retardance and damage resistance of an insulated wire especially. With the goal.

  As a result of intensive studies to solve the above problems, the present inventor intervenes a specific substance at the interface between the metal hydroxide and the specific resin, and the total amount of the specific substance and the metal hydroxide is In addition to containing the specific resin in a specific ratio and including the polyorganosiloxane in a predetermined ratio with respect to the specific resin, flame resistance and damage resistance of the insulated wire The inventors have found that the properties can be improved, and have completed the present invention.

  That is, the present invention relates to a polyolefin resin containing an ethylene polymer in which an oxygen atom is contained in a molecular skeleton, metal hydroxide particles, and an alkyl β-carboxyacrylate adhering to the surface of the metal hydroxide particles. And polyorganosiloxane, the metal hydroxide particles and the alkyl β-carboxyacrylate are contained in a proportion of 20 to 50 parts by mass with respect to 100 parts by mass of the polyolefin resin, and the polyorganosiloxane. Is a flame retardant resin composition characterized by being contained in a proportion of 2 to 10 parts by mass with respect to 100 parts by mass of the polyolefin resin.

  According to this flame retardant resin composition, it is possible to improve the flame retardancy and damage resistance of the insulated wire.

  The reason why the above effect is obtained is not yet clear, but the inventor presumes as follows. That is, β-carboxy acrylate increases the ionic intermolecular interaction between the polyolefin resin and β-carboxy acrylate and between the metal hydroxide particles and β-carboxy acrylate. The bond between the metal hydroxide particles and the metal hydroxide particles is reinforced. In particular, since the polyolefin resin contains an ethylene polymer having an oxygen atom in its molecular skeleton, the ionic relationship between the oxygen atom in the ethylene polymer and the carbonyl group of alkyl β-carboxyacrylate Intermolecular interaction becomes strong, and the bond between the polyolefin resin and the metal hydroxide particles is sufficiently reinforced. On the other hand, polyorganosiloxane, which is generally known as a flame retardant aid, is considered to improve the resistance to external damage by improving the lubricity of the surface of the insulated wire. As a result, the present inventor presumes that the flame retardancy and damage resistance of the insulated wire can be improved without increasing the hardness of the polyolefin resin itself.

  Moreover, this invention is an insulated wire provided with the conductor and the insulating layer which coat | covers the said conductor, and the said insulating layer is comprised with the flame-retardant resin composition mentioned above. Moreover, this invention may be provided with the conductor and the insulating layer which coat | covers the said conductor, The insulated wire formed by bridge | crosslinking the said flame-retardant resin composition may be sufficient as the said insulating layer.

  These insulated wires can improve flame retardancy and damage resistance.

  Furthermore, this invention is a wire harness characterized by having at least one insulated wire as described above.

  When a wire harness is routed in an internal space of an automobile or an electronic device, the internal space of the automobile or electronic device is narrow, and thus the wire harness is likely to come into contact with the inner wall of the automobile or electronic device. The wire harness of the present invention has at least one of the above-described insulated wires, and the above-described insulated wires are excellent not only in flame resistance but also in damage resistance. For this reason, according to the wire harness of the present invention, not only high safety against ignition in automobiles and electronic devices is obtained, but also the insulated wires are damaged during the routing work in the automobiles and electronic devices. Work can be done without

  Furthermore, the present invention comprises an insulated wire having an inner conductor and an insulating layer covering the inner conductor, and a sheath covering the insulated wire, wherein at least one of the insulating layer and the sheath is the above-mentioned flame retardant resin. A cable comprising a composition or formed by crosslinking the flame retardant resin composition described above.

  In the flame-retardant resin composition, the alkyl β-carboxyacrylate is, for example, ethyl β-carboxyacrylate.

  In the flame retardant resin composition, the polyolefin resin is preferably composed of at least one selected from the group consisting of an ethylene ethyl acrylate copolymer and an ethylene vinyl acetate copolymer. In this case, the damage resistance of the insulated wire can be further improved.

  ADVANTAGE OF THE INVENTION According to this invention, the flame-retardant resin composition which can improve the flame retardance and external damage resistance of an insulated wire, an insulated wire, a wire harness, and a cable are 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.

  Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 and 2.

[cable]
FIG. 1 is a partial side view showing an embodiment of a cable according to the present invention, and FIG. 2 is a sectional view taken along line II-II in FIG. As shown in FIGS. 1 and 2, the cable 10 includes an insulated wire 1, a braid 2 that surrounds the insulated wire 1, and a sheath 3 that covers the braid 2. The insulated wire 1 includes an inner conductor 4 and an insulating layer 5 that covers the inner conductor 4.

  Here, the insulating layer 5 is composed of a flame retardant resin composition, and the flame retardant resin composition includes a polyolefin resin containing an ethylene polymer in which an oxygen atom is contained in a molecular skeleton. And metal hydroxide particles, alkyl β-carboxyacrylate adhering to the surface of the metal hydroxide particles, and polyorganosiloxane. And the particle | grains which consist of metal hydroxide particle | grains and (beta) -carboxy acrylate alkyl are contained in the ratio of 20-50 mass parts with respect to 100 mass parts of said polyolefin resins, and polyorganosiloxane is 100 mass parts of said polyolefin resins. It is contained at a ratio of 2 to 10 parts by mass.

  According to the cable 10 having such a configuration, the flame retardancy and the damage resistance of the insulated wire 1 can be improved.

  As a reason why such an effect is obtained, the present inventor, as described above, strengthens the bond between the polyolefin resin and the metal hydroxide particles by the alkyl β-carboxyacrylate, and uses the polyorganosiloxane to form the insulated wire 1. I suspect that this is due to improved lubricity.

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

(Inner conductor)
First, the inner conductor 4 is prepared. The inner conductor 4 may be composed of only one strand, or may be configured by bundling a plurality of strands. Further, the inner conductor 4 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 adheres to the surface of a polyolefin resin containing an ethylene polymer in which an oxygen atom is contained in the molecular skeleton, metal hydroxide particles, and metal hydroxide particles. It contains β-carboxy acrylate alkyl and polyorganosiloxane.

(Polyolefin resin)
As described above, the polyolefin resin includes an ethylene polymer in which an oxygen atom is contained in the molecular skeleton. Here, said ethylene polymer means what contains the structural unit derived from ethylene. Examples of the ethylene polymer as described above include ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate copolymer, and ethylene-ethyl methacrylate copolymer. It can use individually or in combination of 2 or more types.

  Thus, when an ethylene polymer containing an oxygen atom in the molecular skeleton is used, the ionic intermolecular interaction between the oxygen atom and the carbonyl group of alkyl β-carboxyacrylate is strengthened, Compared to the case of using an ethylene-based polymer having no oxygen atom in the molecular skeleton, the damage resistance of the insulated wire can be further improved.

  Among them, as an ethylene polymer, ionic intermolecular interaction with β-carboxyalkyl acrylate can be further enhanced, and wear resistance and trauma resistance can be further improved. Therefore, EVA, EEA Or a mixture thereof is preferred.

  As EVA, what contains 20 mass% or more of structural units derived from VA is preferable, and as EEA, what contains 70 mass% or more of structural units derived from ethylene is preferable.

  When a mixture of EVA and EEA is used as the ethylene-based polymer, EVA is included in a proportion of 30 to 70% by mass with a mixed resin of EVA and EEA being 100% by mass, and EEA is 70 to 30%. It is preferable that it is contained in the ratio of mass%. In this case, as compared with the case where the content of EVA or EEA is out of the numerical range, not only the flame retardancy and the scratch resistance but also the heat resistance can be further improved.

(Metal hydroxide particles)
The metal hydroxide particles are made of a metal hydroxide, and examples of the metal hydroxide include magnesium hydroxide, calcium hydroxide, and aluminum hydroxide. Among these, magnesium hydroxide is preferable. This is because the ionic intermolecular interaction with the alkyl β-carboxyacrylate can be further enhanced, and the wear resistance and the trauma resistance can be further improved.

(Alkyl β-carboxyacrylate)
Examples of the β-carboxyacrylate include methyl β-carboxyacrylate, ethyl β-carboxyacrylate, and propyl β-carboxyacrylate. Of these, ethyl β-carboxyacrylate is most preferable.

  The particle | grains which consist of metal hydroxide particle | grains and (beta) -carboxyethyl acrylate are contained in the ratio of 20-50 mass parts with respect to 100 mass parts of polyolefin resin as mentioned above. If the metal hydroxide particles and ethyl β-carboxyacrylate are contained in a proportion of less than 20 parts by mass with respect to 100 parts by mass of the polyolefin resin, the flame retardancy of the insulated wire 10 is significantly reduced. Further, when the metal hydroxide particles and ethyl β-carboxyacrylate are contained in a proportion exceeding 50 parts by mass with respect to 100 parts by mass of the polyolefin resin, the damage resistance is remarkably lowered.

  It is preferable that the metal hydroxide particles and the ethyl β-carboxyacrylate are contained in a proportion of 30 to 45 parts by mass with respect to 100 parts by mass of the polyolefin resin because the damage resistance is further improved.

  Examples of the method for attaching the alkyl β-carboxyacrylate to the surface of the metal hydroxide particles include a method in which the metal hydroxide particles are surface-treated with an alkyl β-carboxyacrylate. Specifically, after adding β-carboxyacrylate to the surface of metal hydroxide particles, the mixture is obtained by adding and mixing alkyl β-carboxyacrylate to metal hydroxide particles. The mixture can be dried at 40 to 75 ° C. for 10 to 40 minutes, and the dried mixture can be pulverized with a Henschel mixer, an atomizer or the like.

  Here, the adhesion amount of the β-carboxyalkyl acrylate to the metal hydroxide particles is not particularly limited, but may be 0.05 to 5 parts by mass with respect to 100 parts by mass of the metal hydroxide. It is preferable for the reason of improving the resistance to external damage, and more preferably 0.1 to 3 parts by mass.

(Polyorganosiloxane)
The polyorganosiloxane functions as a flame retardant aid, and examples of the polyorganosiloxane include silicone powder, silicone gum, and silicone resin. 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. Can be mentioned.

  As described above, the polyorganosiloxane is contained in a ratio of 2 to 10 parts by mass with respect to 100 parts by mass of the polyolefin resin, but preferably in a ratio of 2 to 10 parts by mass with respect to 100 parts by mass of the polyolefin resin. More preferably, it is contained in a ratio of 2 to 7 parts by mass with respect to 100 parts by mass of the polyolefin resin. If it is less than 2 parts by mass, the trauma resistance or flame retardancy is remarkably reduced, and if it exceeds 10 parts by mass, the mechanical properties (particularly mechanical strength) or the trauma resistance is remarkably reduced.

  The flame retardant resin composition is filled with a flame retardant aid, an antioxidant, an ultraviolet absorber, an ultraviolet degradation inhibitor, an antistatic agent, a processing aid, a colorant, a lubricant, a crosslinking aid, an inorganic filler, and the like. An agent may be included.

  The flame retardant resin composition can be obtained, for example, by kneading the polyolefin resin, a metal hydroxide particle having an alkyl β-carboxyacrylate attached thereto, and polyorganosiloxane. 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.

  Next, the inner conductor 4 is covered with the flame retardant resin composition, and the insulating layer 5 is formed on the inner conductor 4. The coating of the flame retardant resin composition may be performed by, for example, extruding the flame retardant resin composition into a tube shape by extrusion molding so as to adhere to the surface of the internal conductor 4, or in a die containing the flame retardant resin composition. 4 can be performed.

(Braid)
Next, the insulated wire 1 is surrounded by the braid 2. The braid 2 functions as an outer conductor and is made of a metal such as an annealed copper wire.

(sheath)
Finally, the braid 2 is covered with the flame retardant resin composition, and the flame retardant resin composition is subjected to a crosslinking treatment. In this way, a sheath 3 covering the braid 2 is obtained. The sheath 3 protects the insulating layer 5 from physical or chemical damage.

  The cable 10 is obtained as described above.

  As described above, according to the cable 10, the flame retardancy and the damage resistance of the insulated wire 1 can be improved. For this reason, the cable 10 is particularly useful for at least one cable constituting the wire harness.

  That is, when the wire harness is routed in the internal space of an automobile or an electronic device, the internal space of the automobile or the electronic device is narrow, and thus the wire harness is likely to come into contact with the inner wall of the automobile or the electronic device. In that respect, since the insulated wire 1 can improve the flame retardancy and the damage resistance, it is possible to obtain high safety against ignition in automobiles and electronic devices, as well as in automobiles and electronic devices. In the routing work, the work can be performed without damaging the insulated wire 1.

  The present invention is not limited to the above embodiment. For example, in the above embodiment, the flame-retardant resin composition may be further subjected to a crosslinking treatment by electron beam irradiation in order to further improve the trauma resistance.

  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 1-6 and Comparative Examples 1-4)
EEA, EVA, magnesium hydroxide, β-carboxyethyl acrylate, polyorganosiloxane, and anti-aging agent were blended at the blending ratios shown in Tables 1 and 2 and kneaded at 140 ° C for 15 minutes with a Banbury mixer. A functional resin composition was obtained. In addition, the mixing | blending of magnesium hydroxide and (beta) -carboxy acrylate was performed in the state which surface-treated magnesium hydroxide in advance with (beta) -carboxy acrylate. At this time, magnesium hydroxide particles surface-treated with ethyl β-carboxyacrylate were obtained as follows. That is, first, β-carboxyethyl acrylate was added to the magnesium hydroxide particles at a ratio shown in Tables 1 and 2 and mixed with stirring to obtain a mixture. Next, this mixture was dried at 60 ° C. for 50 minutes, and the dried mixture was pulverized with a Henschel mixer. Thus, magnesium hydroxide particles surface-treated with ethyl β-carboxyacrylate were obtained.

The above-mentioned EEA, EVA, magnesium hydroxide and ethyl β-carboxyacrylate were used as the polyorganosiloxane and the anti-aging agent, respectively.
(1) EEA
A710 (trade name, manufactured by Mitsui DuPont Polychemical Co., Ltd.)
(2) EVA
V-5274 (trade name, manufactured by Mitsui DuPont Polychemical Co., Ltd., content of structural units derived from VA: 17% by mass)
(3) Magnesium hydroxide kisuma 5L (trade name, manufactured by Kyowa Chemical Co., Ltd.)
(4) Ethyl β-carboxyacrylate C-800 (trade name, manufactured by Lubrizol)
(5) Polyorganosiloxane X-21-3043 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.)
(6) Anti-aging agent
Irganox1010 (trade name, manufactured by Ciba Japan)

Thereafter, the above flame-retardant resin composition is extruded into a tube shape by an extruder, and flame-retardant so as to have a thickness of 0.7 mm on the conductor (58 wires / wire diameter 0.26 mm). The resin composition was coated. Thus, an insulated wire was obtained.

  About the insulated wires of Examples 1 to 6 and Comparative Examples 1 to 4 obtained as described above, the measurement of the tensile breaking strength and the tensile breaking elongation, and the evaluation of the trauma resistance and the flame resistance are as follows. I went.

(Tensile strength at break)
About the insulated wire of Examples 1-6 and Comparative Examples 1-4, the tensile breaking strength was measured on the test conditions of the tensile speed of 200 mm / min and the distance between marked lines of 20 mm. And the insulated wire whose tensile breaking strength is 10 Mpa or more was made into the pass, and the insulated wire which was less than 10 Mpa was made into the failure.

(Tensile breaking elongation)
For the insulated wires of Examples 1 to 6 and Comparative Examples 1 to 4, tensile elongation at break was measured under test conditions of a tensile speed of 200 mm / min and a distance between marked lines of 20 mm. And the insulated wire whose tensile breaking elongation is 300% or more was set as the pass, and the insulated wire which is less than 300% was set as the failure.

(Trauma resistance)
About the insulated wire of Examples 1-6 and Comparative Examples 1-4, the scratch test by the diamond indenter whose tip diameter is 0.3 mm was done at the speed of 100 mm / min. If the starting load with scratches by this diamond indenter was 1000 gf or more, the test was accepted, and if it was less than 1000 gf, the test was rejected.

(Flame retardance)
About the insulated wire of Examples 1-6 and Comparative Examples 1-4, the 45 degree inclination combustion test of ISO6722 was done, and the flame retardance evaluation of the insulated wire was performed as follows. That is, an insulated wire in which an upper part of 50 mm or more of a 600 mm long wire sample remained and self-extinguished within 70 seconds was accepted, and an insulated wire that was not so was rejected.

  In addition, about evaluation results of tensile breaking strength, tensile breaking elongation, trauma resistance and flame resistance, in Table 1 and Table 2, when it is acceptable, it is indicated as “O”, and when it is unacceptable “×” is displayed.

  From the results shown in Table 1 and Table 2, it was found that the insulated wires of Examples 1 to 6 were excellent in flame retardancy and damage resistance as compared with the insulated wires of Comparative Examples 1 to 4.

  From this, it was confirmed that according to the flame retardant resin composition of the present invention, the flame retardancy and the trauma resistance of the insulated wire can be improved.

  DESCRIPTION OF SYMBOLS 1 ... Insulated wire, 2 ... Coarse, 3 ... Sheath, 4 ... Internal conductor, 5 ... Insulating layer, 10 ... Cable.

Claims (7)

A polyolefin resin containing an ethylene polymer containing an oxygen atom in the molecular skeleton;
Metal hydroxide particles,
An alkyl β-carboxyacrylate adhering to the surface of the metal hydroxide particles;
Polyorganosiloxane,
Containing
The metal hydroxide particles and the alkyl β-carboxyacrylate are included in a proportion of 20 to 50 parts by mass with respect to 100 parts by mass of the polyolefin resin.
The polyorganosiloxane is contained in a ratio of 2 to 10 parts by mass with respect to 100 parts by mass of the polyolefin resin.
A flame retardant resin composition. The alkyl β-carboxyacrylate is ethyl β-carboxyacrylate;
The flame-retardant resin composition according to claim 1.   The flame retardant resin composition according to claim 1 or 2, wherein the polyolefin resin is composed of at least one selected from the group consisting of an ethylene ethyl acrylate copolymer and an ethylene vinyl acetate copolymer. Conductors,
An insulating layer covering the conductor;
With
The insulating layer is composed of the flame retardant resin composition according to any one of claims 1 to 3,
Insulated wire characterized by Conductors,
An insulating layer covering the conductor;
With
The insulating layer is formed by crosslinking the flame retardant resin composition according to any one of claims 1 to 3.
Insulated wire characterized by Having at least one insulated wire according to claim 4 or 5,
Wire harness characterized by An insulated wire having an inner conductor and an insulating layer covering the inner conductor;
A sheath for covering the insulated wire,
At least one of the insulating layer and the sheath is composed of the flame retardant resin composition according to any one of claims 1 to 3, or the flame retardant according to any one of claims 1 to 3. A cable obtained by crosslinking a functional resin composition.

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