JP3068422B2 - Insulated wire - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a covered electric wire suitable as an electric wire for automobiles and internal wiring of electronic equipment.
Has excellent flame retardancy, tensile properties, heat resistance and wear resistance,
The present invention relates to a coated electric wire which does not generate a large amount of smoke or harmful corrosive gas during combustion, has good end workability in a coating stripping step, and has excellent productivity by high-speed extrusion.

[0002]

2. Description of the Related Art JASO D611 and JIS C3
Various characteristics such as flame retardancy, tensile properties, heat resistance, and wear resistance are required for automobile wires and wires used for internal wiring of electronic devices defined in 406. For this reason, as a material for covering these electric wires, a polyolefin compound containing PVC or a halogen-based flame retardant has been mainly used. However, since such electric wires have a problem that a large amount of smoke and corrosive gas are generated during combustion, in recent years, research has been conducted on electric wires that generate little smoke and do not generate corrosive gas during combustion. Have been. Therefore, it has been studied to use an ethylene copolymer (ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer, etc.) highly filled with metal hydrate as a coating material for these electric wires. I have. But,
Electric wires coated with these materials are not satisfactory in terms of mechanical properties such as tensile strength and abrasion resistance, and heat resistance in terms of electric wires for automobiles and electric wires used for internal wiring of electronic devices. An example of an electric wire coated with a polypropylene composition having excellent mechanical properties and heat resistance is disclosed in
Although disclosed in JP-A-131052, when an electric wire coated with this composition is used as an electric wire for an automobile, the stress at break is about 2 to 10 MPa and the tensile strength is insufficient, as in the example. Was a problem. The wire extrusion speed is about 10 to 80 m / min, which is practically an industrially necessary wire extrusion speed of 40 to 40 m / min.
There was also a problem that molding was possible only at an extremely low speed as compared with 0 to 500 m / min, and the cost was high. In addition, when the outer periphery of the conductor is coated with a composition highly filled with metal hydrate, in the step of stripping the end of the electric wire using a wire stripper or a casting machine, a coating residue is generated and poor contact with a terminal to be attached is caused. There was a problem of getting up.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide flame retardancy, tensile properties, heat resistance and abrasion resistance required for electric wires for automobiles and internal wiring of electronic equipment, and to produce a large amount of smoke during combustion. It does not generate harmful corrosive gas and has good end workability in the coating stripping process.Furthermore, it is possible to produce high-speed processing by coating the outer periphery of the conductor, which is an important element for manufacturing inexpensive electric wires Is to provide an electric wire.

[0004]

In order to achieve the above object, the present invention provides: (1) (a) an ethylene / propylene random copolymer;
At least 40% by weight of a polypropylene-based resin containing at least 50% by weight, (b) 1.5 to 30% by weight of a modified polyethylene modified with an unsaturated carboxylic acid or a derivative thereof, and (c) 48% by weight of an ethylene-based copolymer % Based on 100 parts by weight of the resin mixture containing the resin component as a resin component.
(D) a coated wire wherein a coating of a composition comprising 50 to 180 parts by weight of a metal hydrate is formed on the outer periphery of the conductor; and (2) the resin mixture further comprises (e) Aromatic vinyl-
The coated electric wire according to the above (1), which contains the diene block copolymer in a range of 20% by weight or less, is provided. Preferred embodiments of the coated electric wire of the present invention include the following. (3) The coated electric wire according to (1), wherein the (a) polypropylene-based resin contains 50% by weight or more of an ethylene / propylene random copolymer having an ethylene component ratio of 0.5 to 6.0% by weight. (4) The coated electric wire according to the above (1), wherein the (b) modified polyethylene is a polyethylene modified with maleic anhydride, (5) the (c) ethylene-based copolymer is ethylene-vinyl acetate copolymer. (1) The coated electric wire according to the above (1), which is a polymer, an ethylene / ethyl acrylate copolymer, or a mixture thereof; (6) The (1) above, wherein the (d) metal hydrate is magnesium hydroxide. (7) The coated electric wire according to the above (2), wherein the (e) aromatic vinyl-diene block copolymer is a styrene-hydrogenated butadiene-styrene copolymer.

First, each component used in the composition of the present invention, which is coated on the outer periphery of the conductor and becomes a covering material of the electric wire, will be described. (A) polypropylene resin used in the polypropylene resin present invention are those containing the ethylene-propylene random copolymer 50 wt%, as the polypropylene resin other than the ethylene-propylene random copolymer, ethylene
Propylene block copolymer, polypropylene homopolymer, propylene / 1-butene block copolymer, propylene / 1-butene random copolymer, propylene / 4-
Methylpentene-1 block copolymer, propylene / 4
-Methylpentene-1 random copolymer, propylene
One or more resins selected from a 1-hexene block copolymer and a propylene / 1-hexene random copolymer may be used as a mixture. In particular, the proportion of the ethylene / propylene random copolymer is at least 60% by weight, preferably at least 70% by weight, more preferably at least 80% by weight.
It is preferable to use one having a weight percentage of at least. The ethylene / propylene random copolymer used herein is one in which ethylene and propylene are polymerized in a substantially random manner, preferably having an ethylene content of 0.5 to 6% by weight, more preferably 1 to 6% by weight. It is 5% by weight. In the random copolymer of the present invention, ethylene is bonded to propylene in a substantially random manner and, unlike the block copolymer, hardly takes a domain structure. A random copolymer having an ethylene content of less than 0.5% by weight is not preferred because it has poor filler receptivity and a large decrease in tensile strength and elongation when kneaded with a metal hydrate or the like. On the other hand, those having an ethylene content of more than 6% by weight are not preferred because of poor heat resistance. When the proportion of the ethylene-propylene random copolymer in the polypropylene-based resin is 50% by weight or more, an electric wire whose outer periphery is covered with such a composition has large tensile strength and elongation,
Because of its excellent flexibility, wiring inside automobiles and electronic devices can be performed more freely. The melt flow rate (MFR) of the polypropylene resin is 0.1 to 20 g / 10
Min (load 2.16 kgf, 230 ° C.), and more preferably 0.1 to 10 g / 10 min (load 2.16 kgf, 230 ° C.). ethylene·
Melt flow rate of propylene random copolymer (M
FR) is 0.5 to 10 g / 10 min (load 2.16 kg
f, 230 ° C.).

(B) Modified polyethylene In the present invention, the modified polyethylene used as a resin component in the resin mixture is a polyethylene which is an unsaturated carboxylic acid and / or a derivative thereof (hereinafter, abbreviated as "unsaturated carboxylic acid or the like"). It is denatured. In order to modify polyethylene with an unsaturated carboxylic acid or the like, for example, a method of melting and kneading polyethylene and an unsaturated carboxylic acid or the like in the presence of a peroxide at a temperature equal to or higher than the half-life temperature of the peroxide for 1 minute or more is used. Can be used. Further, the above polyethylene may be reacted with the above unsaturated carboxylic acid or the like in the presence of an inert solvent such as hexane, heptane, benzene or toluene. The proportions of the unsaturated carboxylic acid and peroxide kneaded with the polyethylene are preferably 0.01 to 1.0 part by weight and 0.01 to 0.5 part by weight, respectively, based on 100 parts by weight of the polyethylene. Examples of polyethylene include very low density polyethylene (VLDPE) and linear low density polyethylene (LLD).
PE), low density polyethylene (LDPE), medium density polyethylene (MDPE), and / or high density polyethylene (HDPE). Its MFR is 0.5-1
Those having a range of 0 g / 10 minutes (load: 2.16 kgf, 190 ° C.) are preferable. As the unsaturated carboxylic acid, for example, maleic acid, itaconic acid and fumaric acid are used. Examples of the unsaturated carboxylic acid derivative include maleic acid monoester, maleic acid diester, maleic anhydride, itaconic acid monoester, itaconic acid diester, itaconic anhydride, fumaric acid monoester, fumaric acid diester and the like. As the modified polyethylene, a polyethylene modified with maleic anhydride is preferable.

(C) Ethylene copolymer Ethylene copolymers include ethylene / vinyl acetate copolymer, ethylene / acrylate copolymer, ethylene / methacrylate copolymer, ethylene / acrylic acid copolymer Ethylene copolymers such as a polymer, an ethylene / methacrylic acid copolymer, and an ethylene / propylene rubber are exemplified. Among these ethylene-based copolymers, ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer such as ethylene-ethyl acrylate copolymer,
Or a mixture thereof is preferred, and an ethylene / vinyl acetate copolymer is particularly preferred. In these ethylene copolymers, those having a comonomer ratio of 8 to 30% by weight are particularly preferred. The MFR is 0.1 to 10 g /
A range of 10 minutes (load 2.16 kgf, 190 ° C.) is preferable. (D) Metal Hydrate In the present invention, the type of metal hydrate to be blended in the coating composition is not particularly limited. For example, aluminum hydroxide, magnesium hydroxide, hydrated aluminum silicate, hydrated magnesium silicate And inorganic compounds having a hydroxyl group or water of crystallization such as basic magnesium carbonate, aluminum orthosilicate and hydrotalcite. These metal hydrates may be used alone or in combination of two or more, and the most preferred is magnesium hydroxide. It is preferable that these metal hydrates have a crystal particle diameter in the range of 0.3 to 1.0 μm and have almost no aggregation. Such a material includes, for example, Kisuma 5 (registered trademark), a magnesium hydroxide-based flame retardant manufactured by Kyowa Chemical Industry Co., Ltd., and a surface-treated grade such as Kisuma 5A, 5B, 5E, or 5J is particularly preferable. .

(E) Aromatic vinyl-diene block copolymer In a composition which is a covering material for electric wires, in addition to the above-mentioned polypropylene resin, modified polyethylene, metal hydrate and ethylene copolymer, aromatic vinyl-diene block copolymer A group vinyl-diene block copolymer can also be added. This consists of a block A consisting essentially of a polymer of an aromatic vinyl compound such as styrene and a block B consisting essentially of a polymer of a diene compound such as butadiene.
Is a block copolymer containing at least one of the following. The block A is preferably a block of polystyrene, poly o-methylstyrene, poly m-methylstyrene, poly p-methylstyrene, poly α-methylstyrene, polyβ-methylstyrene, polydimethylstyrene, polytrimethylstyrene, or the like. The block B is preferably a block of polybutadiene, polyisoprene, or a butadiene / isoprene copolymer. Examples of the block copolymer used in the present invention include a polystyrene-polybutadiene-polystyrene block copolymer, a polystyrene-polyisoprene-polystyrene block copolymer, and a poly-α-methylstyrene-polybutadiene-polyα-methylstyrene block copolymer. Polymer, poly α-methylstyrene-polyisoprene-polyα-methylstyrene block copolymer, poly β-methylstyrene-polybutadiene-polyβ-methylstyrene block copolymer, polyβ-methylstyrene-polyisoprene-poly Examples include β-methylstyrene block copolymers and the like, and hydrides of these block copolymers. In the present invention, block A
Is hardly hydrogenated, and a block copolymer in which block B is selectively hydrogenated is particularly preferable. For example, a styrene-hydrogenated butadiene-styrene copolymer (=
Styrene / ethylene / butylene / styrene copolymer = S
EBS). The above block copolymers may be used as a mixture of two or more.

Next, (a) polypropylene resin, (b) modified polyethylene, (c) ethylene copolymer, (d) metal hydrate, (e) in the composition used for the coated electric wire of the present invention. Each ratio of the aromatic vinyl-diene block copolymer will be described. The proportion of the (a) polypropylene resin in the composition is the total amount of the resin components, that is, (a) polypropylene resin, (b) modified polyethylene and (c) ethylene copolymer, or these resin components. Further, it is preferably 40% by weight or more of the total amount of the resin mixture containing the (e) aromatic vinyl-diene block copolymer. When this proportion is 40% by weight or more, the wire coated with the composition has a lower heating deformation rate and has particularly good mechanical properties such as abrasion resistance and tensile properties.
It is suitable as an internal wiring material for automobile electric wires and electronic devices. (B) The compounding amount of the modified polyethylene is in the range of 1.5 to 30% by weight of the resin mixture, preferably 5 to 20%.
% By weight. If the amount of the modified polyethylene in the resin mixture is less than 1.5% by weight, the wear resistance and tensile properties of the electric wire are not sufficient, and if the amount of the modified polyethylene exceeds 30% by weight, the composition Since the fluidity of the wire is reduced, it is not possible to perform high-speed extrusion coating on the electric wire. In addition, by blending the ethylene copolymer (c) such as an ethylene-vinyl acetate copolymer in the coating, the flame retardancy of the electric wire is improved. However, the ratio is 48 to the total amount of the resin components (resin mixture) in the coating composition, that is, 100 parts by weight of the total amount of (a) polypropylene-based resin, (b) modified polyethylene, and (c) ethylene-based copolymer. It must be less than weight percent. If this ratio is 48% by weight or more, the heat resistance, tensile properties, and end workability of the coated electric wire are undesirably reduced. In order to improve the flame retardancy, the total amount of the resin components in the composition is 10%.
It is preferably at least 48% by weight and less than 48% by weight. The compounding amount of the metal hydrate (d) in the composition for covering an electric wire is as follows:
It is in the range of 50 to 180 parts by weight, preferably 65 to 150 parts by weight, based on 0 part by weight. If the amount of the metal hydrate is less than 50 parts by weight, sufficient flame retardancy cannot be obtained as an electric wire for automobiles and internal wiring of electronic devices. On the other hand, if it exceeds 180 parts by weight, the tensile strength and elongation of the electric wire are significantly reduced. In addition, the extrusion processability for manufacturing the electric wire is also unpreferably reduced.

Furthermore, when the (e) aromatic vinyl-diene block copolymer is blended, the tensile strength and elongation of the coated electric wire can be improved. The total amount, that is, the resin mixture ((a)
+ (B) + (c) + (e)) is preferably 20% by weight or less, more preferably 5 to 15% by weight. If the amount is more than 20% by weight of the total amount of the resin components, the moldability is remarkably reduced, which is not preferable. Further, in order to improve the flame retardancy of the obtained electric wire, carbon black, red phosphorus, a tin compound, fibrous magnesium hydroxide, or the like may be added to the composition. Also, if necessary, a polyethylene resin,
Copper damage inhibitors, antioxidants, ultraviolet absorbers, dispersants, pigments, and the like may be added.

The coated electric wire of the present invention is produced by extrusion-coating the above composition as a coating layer around a conductor using an ordinary extruder for manufacturing electric wires. The temperature of the extruder at this time is preferably about 190 ° C. in the cylinder and about 200 ° C. in the crosshead. In addition,
The coated electric wire of the present invention includes all the electric wires covered with the above-described composition as a coating layer on the outer periphery of the conductor, and the structure thereof is not particularly limited. The thickness of the coating layer, the thickness of the conductor, and the like are not particularly different from those of the related art. These vary depending on the type and use of the electric wire, and can be set as appropriate. 1 to 3 show examples of the structure of the coated electric wire of the present invention.
FIG. 1 shows an example of a first electric wire of the present invention in which a coating layer 2 is formed as an insulating layer on the outer periphery of a conductor 1 made of a single wire or a stranded wire, and FIG. This is a second example of an electric wire according to the present invention in which a shielding layer 4 is provided in this order, and a coating layer 22 is provided on the outer periphery thereof as a protective layer (sheath). FIG. 3A shows a cordel insulator 5 wound around the inner conductor 11, an outer conductor 21 is provided on the outer periphery, and a coating layer 32 is provided on the outer periphery as an insulating protective layer (sheath). The cross section of the coaxial cable
FIG. 3B shows the outer conductor 2 along the line CC in FIG.
1 shows a partially cutaway front view of a coaxial cable in which only the first and covering layers 32 are cut, and is a third example of the electric wire of the present invention.

[0012]

The present invention will be described below in more detail with reference to Examples and Comparative Examples. Examples 1 to 13 and Comparative Examples 1 to 8 The components shown in Tables 1 and 2 were dry-blended at room temperature at respective mixing ratios, and kneaded at a kneading temperature of 18 using a Banbury mixer.
The composition corresponding to each Example and Comparative Example was obtained by melt-kneading under the conditions of 0 ° C. and a kneading time of 15 minutes. Next, using a general-purpose wire covering apparatus, the obtained composition was extrusion-coated with 0.35 mm thickness on a soft copper wire having a conductor diameter of 0.9 mm to produce a covered wire. For each of the coated electric wires, the tensile strength (MPa) and elongation (%) of the coating layer were measured by a tensile test.
The test was performed at a mark interval of 25 mm and a tensile speed of 50 mm / min. In addition, JIS C 3005
It evaluated according to. The flame contact time was 15 seconds, and the time after the flame was gently removed until the flame disappeared naturally (horizontal burning time) was measured. As the evaluation of the heat resistance of the coating layer, the heating deformation rate of the coated electric wire was evaluated according to JIS C 3005. The test temperature was 120 ° C., the load was 306 gf, and the coating layer having a deformation rate of 30% or less was regarded as acceptable. The wear resistance of electric wires is measured according to JASO standard (JAPANESE AUTOMOBILE STAN
DARD ORGANIZATION), based on the abrasion tape method described on page 9 of the Appendix, “Nominal” 0.3 to 0.5 in Appendix Table 4.
(The weight of the weight was 450 g), the minimum abrasion resistance was measured. Those with a minimum abrasion resistance of 457 mm or more were judged as acceptable (O).

The evaluation of the end processability of the electric wire is as follows: ○ when the length of the coating material residue generated by using a casting machine is 0.3 mm or less, Δ; Those having a diameter of 0.6 mm or more were evaluated as x. The basis for this criterion is that when the coating material residue was 0.3 mm or less, there was no problem when processing the end of the coated electric wire, but if it was larger than that, there was a problem that contact failure occurred in the terminal connection process. by. Regarding the extrudability of each composition, an extruder having a diameter of 50 mm was used at an extrusion temperature of 200 mm.
The evaluation was performed by coating a 0.9 mm soft copper wire at ℃.
If the extrusion speed is 400 m / min or more,
Those with 0 to 400 m / min were evaluated as Δ, and those with 100 m / min or less were evaluated as x. The test sample for evaluating the flame retardancy, heat resistance, abrasion resistance and end workability of the covered electric wire was basically formed at 400 m / min. For a material that can be formed only at an extrusion speed lower than this, the material having the highest extrusion speed of the material was used as a sample.
Tables 1 and 2 summarize the evaluation results.

[0014]

[Table 1]

[0015]

[Table 2]

As is evident from the results shown in Tables 1 and 2, the coated electric wires of the respective examples have excellent mechanical strength, elongation, flame retardancy, heat resistance and abrasion resistance. It is also excellent in the end processability of the electric wire and the extrudability of the composition (coating). On the other hand, each comparative example is inferior in the end processability of the electric wire and the extrudability of the composition, and is inferior in one or more of the electric wire characteristics, and is not satisfactory as a covered electric wire. Absent.

[0017]

According to the present invention, the coated electric wire is made of ethylene propylene.
Polypropylene resin containing 50% by weight or more of renrandom copolymer, modified polyethylene modified with unsaturated carboxylic acid or derivative thereof, and ethylene copolymer such as ethylene / vinyl acetate copolymer The outer periphery of the conductor is coated with a composition obtained by blending a metal hydrate with a resin mixture containing as an essential resin component, so that excellent flame retardancy required for internal wiring of automobile electric wires and electronic devices, machinery It has properties, heat resistance and abrasion resistance, and has good end workability. Further, when the composition contains an aromatic vinyl-diene block copolymer, the mechanical properties are further improved. Further, since the composition coated in the coated electric wire of the present invention is excellent in high-speed extrusion moldability, the productivity of manufacturing the coated electric wire is high, the cost merit as the coated electric wire is great, and the industrial value is extremely high.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a first electric wire example of the present invention in which a coating layer is formed as an insulating layer on the outer periphery of a conductor.

FIG. 2 is a cross-sectional view of a second example of an electric wire according to the present invention in which an insulating layer and a shielding layer are provided on the outer periphery of a conductor, and a coating layer is provided on the outer periphery as a protective layer.

FIG. 3 (A) is a coaxial cable in which a cordel insulator is wound around the outer periphery of an inner conductor, an outer conductor is provided on the outer periphery, and a coating layer is provided on the outer periphery as an insulating protective layer. FIG. 3B is a cross-sectional view of a third example of the electric wire according to the present invention, and FIG. 3B is a cross-sectional view of a coaxial cable in which only the outer conductor and the coating layer are cut along CC in FIG. It is a partial notch front view. DESCRIPTION OF SYMBOLS 1 Conductor 2 Coating layer (insulating layer) 3 Insulating layer 4 Shielding layer 5 Cordel insulator 11 Internal conductor 21 External conductor 22 Coating layer (protective layer) 32 Coating layer (insulating layer)

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI C08L 23/08 C08L 23/10 23/10 H01B 7/18 Z (72) Inventor Yasuo Kamei 44-3 Yamaki, Ichihara-shi, Chiba (56) References JP-A-5-54723 (JP, A) JP-A-5-32830 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01B 7/02 H01B 7 / 17-7/29 H01B 3/44 C08K 3/22

Claims (2)

(57) [Claims] 1. A method for producing ethylene and propylene random
40% by weight or more of a polypropylene-based resin containing 50% by weight or more of a polymer , (b) 1.5 to 30% by weight of a modified polyethylene modified with an unsaturated carboxylic acid or a derivative thereof, and (c) an ethylene-based copolymer Was formed on the outer periphery of the conductor by mixing (d) 50 to 180 parts by weight of a metal hydrate with 100 parts by weight of a resin mixture containing less than 48% by weight as a resin component. A covered electric wire characterized by the above-mentioned. 2. The coated electric wire according to claim 1, wherein the resin mixture further contains (e) an aromatic vinyl-diene block copolymer in a range of 20% by weight or less.