JP2003183456A - Flame-retardant ethylenic resin composition, covered electric wire obtained using the same and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flame-retardant ethylenic resin composition endowed with excellence in flame retardancy, high-speed processability, mechanical characteristics and-low temperature characteristics, a covered electric wire covered therewith and its manufacturing method. <P>SOLUTION: The flame-retardant ethylenic resin composition comprises 100 pts.wt. of a base resin (A) and 30-180 pts.wt. of a metal hydroxide (B), where the base resin (A) comprises 95-5 wt.% of an LLDPE (A-1) having a polydispersity (Mw/Mn) of 7-20, a melt mass-flow rate of 0.2-5 g/10 min and a density of 0.90-0.96 g/cm<SP>3</SP>and 5-95 wt.% of an LLDPE (A-2) having a polydispersity (Mw/Mn) of from 2 to 7 exclusive, a melt mass-flow rate of 0.2-10 g/10 min and a density of 0.86-0.96 g/cm<SP>3</SP>. The covered electric wire is covered with the resin composition. The manufacturing method of the covered electric wire comprises covering an electric wire with the resin composition at a wire speed higher than 200 m/min. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a flame-retardant ethylene-based resin composition, a coated electric wire using the same, and a method for producing the same, and more particularly, it has good flame-retardant property and high-speed processability, and is further excellent. The present invention relates to a flame-retardant ethylene-based resin composition having mechanical properties and low-temperature properties, a covered electric wire obtained by using the resin composition, and a method for producing the same. INDUSTRIAL APPLICABILITY The coated electric wire of the present invention can be widely used as an electric wire for automobiles, communication, electric power, and the like.

[0002]

2. Description of the Related Art Conventionally, an ethylene resin composition containing a vinyl chloride resin or a flame retardant containing halogen has been widely used as a coating material for electric wires used for automobiles, communication and electric power. However, in recent years, due to the fact that the vinyl chloride resin and the flame retardant containing halogen generate toxic halogen-containing gas at the time of combustion and the environmental load problem, a resin composition without these concerns has been demanded. .
Therefore, an ethylene-based resin composition containing a metal hydroxide as a flame retardant has been proposed. However, in order to impart flame retardancy, the metal hydroxide has no effect unless it is blended in a larger amount than the flame retardant containing halogen, and high-speed processability cannot be obtained. On the other hand, high speed processability is required in the production of a coated electric wire in which an insulating layer or a sheath layer is coated with an ethylene resin.

In order to solve the above problems, the applicant has
First, Japanese Patent Application No. 10-285992 (JP-A 2000-
95901), a metal hydroxide is used as a flame retardant, and 100 parts by weight of a specific ethylene resin is blended with 10 to 100 parts by weight of an effective amount for imparting flame retardancy, and an organopolysiloxane is blended. Therefore, we proposed an ethylene-based resin composition with high-speed processability and abrasion resistance, but further improvements in mechanical properties (tensile fracture stress, tensile fracture strain) and low-temperature properties (low-temperature brittleness) were required. .

[0004]

In view of the above circumstances, the present invention has improved mechanical properties and low temperature properties of conventional ethylene resin compositions, that is, has good flame retardancy and high-speed processability, A flame-retardant ethylene-based resin composition having further excellent mechanical characteristics and low-temperature characteristics, a coated electric wire obtained by coating the resin composition as an insulating coating layer and / or a sheath coating layer (so-called electric wire coating layer), and The purpose is to provide a manufacturing method thereof.

[0005]

Means for Solving the Problems In order to solve the above-mentioned problems, the inventors of the present invention have intensively studied a combination of an ethylene-based resin as a base resin, and as a result, a specific combination may contain another compounding agent. Without, while maintaining good flame retardancy and high-speed processability, found that a flame-retardant ethylene-based resin composition having excellent mechanical properties and low temperature properties can be obtained,
The present invention has been completed.

That is, according to the first aspect of the present invention,
In the flame-retardant ethylene-based resin composition prepared by mixing 30 to 180 parts by weight of the metal hydroxide (B) with 100 parts by weight of the base resin (A), the base resin (A) has a number average molecular weight (Mn The polydispersity (Mw / Mn) represented by the ratio of the weight average molecular weight (Mw) to 7) is 7 to 20, the melt mass flow rate is 0.2 to 5 g / 10 min, and the density is 0.
90 to 0.96 g / cm ³ of linear ethylene-α-olefin copolymer (A-1) 95 to 5% by weight, polydispersity (Mw / Mn) of 2 to less than 7, melt mass flow rate 0.2-10 g / 10 minutes, and a density of 0.86-0.
A flame-retardant ethylene-based resin composition comprising 96 g / cm ³ of a linear ethylene-α-olefin copolymer (A-2) of 5 to 95% by weight.

According to a second aspect of the present invention, in the first aspect, the linear ethylene-α-olefin copolymer (A-1) is polymerized with a Phillips type catalyst. Chain ethylene-α-olefin copolymer (A
-2) is a polymer which is polymerized with a Ziegler-based catalyst, and a flame-retardant ethylene-based resin composition is provided.

According to a third aspect of the present invention, in the first aspect, the metal hydroxide (B) is a higher fatty acid, a higher fatty acid metal salt, a higher fatty acid ester, a higher fatty acid amide, a higher alcohol, or a hardened oil. 1 selected from the group consisting of titanate coupling agents and silane coupling agents
Provided is a flame-retardant ethylene-based resin composition, which is magnesium hydroxide surface-coated with one or more surface treatment agents.

According to a fourth aspect of the present invention, it has an insulating multi-layer and / or a sheath coating layer formed from the flame-retardant ethylene-based resin composition according to any one of the first to third aspects. A coated electric wire is provided.

According to a fifth aspect of the present invention, the flame-retardant ethylene-based resin composition according to any one of the first to third aspects is extruded on a metal conductor at a linear velocity of more than 200 m / min to insulate it. A method of manufacturing a covered electric wire according to a fourth aspect of the present invention is characterized in that the covering wire and / or the sheath covering layer are coated and formed.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the flame-retardant ethylene resin composition of the present invention and a covered electric wire using the same and a method for producing a covered electric wire will be described in detail for each item.

1. Base Resin (A) The base resin (A) used in the present invention is composed of two kinds of linear ethylene-α-olefin copolymers, that is, the weight average molecular weight (Mn) relative to the number average molecular weight (Mn).
The polydispersity (Mw / Mn) represented by the ratio of w) is 7 to 2
0, preferably 10-18, more preferably 12-1
7 is a linear ethylene-α-olefin copolymer (A
-1) and a linear ethylene-α-olefin copolymer (A) having a polydispersity (Mw / Mn) of 2 to less than 7, preferably 3 to 6, and more preferably 3.5 to 5.5. -2), and the mixing ratio of (A-1) and (A-2) is (A-
1) 95 to 5% by weight, preferably 80 to 20% by weight, more preferably 75 to 25% by weight, and (A-2) 5 to
It is 95% by weight, preferably 20 to 80% by weight, more preferably 25 to 75% by weight.

The difference between the polydispersity index (Mw / Mn) of the linear ethylene-α-olefin copolymer (A-1) and the polydispersity index (Mw / Mn) of (A-2) is 7 or more, It is preferably 8 or more, more preferably 9 or more in order to obtain high-speed processability. In addition, the number average molecular weight (Mn) and the weight average molecular weight (Mw) in the present invention mean the molecular weight converted by polystyrene, respectively. The polydispersity (Mw / Mn) represented by the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is linear ethylene-α-
It is a parameter representing the molecular weight distribution of the olefin copolymers (A-1) and (A-2). The smaller the value, the narrower the molecular weight distribution, and the larger the value, the wider the molecular weight distribution.
Polydispersity (Mw / Mn) is 2 by the latest polymerization technology
A linear ethylene-α-olefin copolymer in the range from 1 to 20 can be produced by an industrialized apparatus. In the present invention, the linear ethylene-α-olefin copolymer (A-1) preferably has a polydispersity (Mw / Mn) in the range of 7 to 20, and is typically polymerized with a Phillips catalyst. However, if less than 7, it is difficult to polymerize with the catalyst and inferior in high speed processability, and if more than 20, it is difficult to polymerize, and mechanical strength, low temperature characteristics and the like are insufficient, which is not preferable. The polydispersity (Mw / Mn) of the linear ethylene-α-olefin copolymer (A-2) is preferably in the range of 2 to less than 7, and is generally 3 to less than 7 in the Ziegler catalyst. However, with Kaminsky catalyst, 2-3.
5 are produced, but those less than 2 are difficult to produce even when using a Kaminsky catalyst and the high-speed processability is poor, and those above 7 are difficult to produce even using a Ziegler catalyst. In addition, mechanical strength and low temperature characteristics are insufficient, which is not preferable.

When the proportion of the linear ethylene-α-olefin copolymer (A-1) having a polydispersity (Mw / Mn) of 7 to 20 exceeds 95% by weight, excellent mechanical properties and low temperature are obtained. No properties can be obtained. On the other hand, if it is less than 5% by weight, high speed processability cannot be obtained. Polydispersity (Mw / Mn)
When the blending ratio of the linear ethylene-α-olefin copolymer (A-2) is 2 to less than 7 exceeds 95% by weight,
High-speed processability cannot be obtained. On the other hand, if it is less than 5% by weight, mechanical strength, low temperature characteristics and the like are insufficient, which is not preferable.

The linear ethylene-α-olefin copolymers (A-1) and (A-2) constituting the base resin (A) of the present invention are composed of ethylene and an α-olefin having 3 to 12 carbon atoms. It is a copolymer. Examples of the α-olefin monomer copolymerized with ethylene include propylene, 1-butene,
Examples thereof include 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene and 4-methyl-1-pentene, butene-1, hexene-1 and octene-1 are preferred. The polymerization reaction is usually performed at a temperature of 0 to 250 ° C.
High pressure (50MPa or more), medium pressure (10-50MP)
It is carried out under polymerization conditions of either a) or low pressure (normal pressure to 10 MPa). Moreover, the polymerization method is not particularly limited, and any method such as a solution polymerization method, a suspension polymerization method, a slurry polymerization method, or a gas phase polymerization method can be used.

A linear ethylene-α-olefin copolymer (A-1) having a polydispersity (Mw / Mn) of 7 to 20.
Can be produced using, for example, a Phillips-based catalyst that has been conventionally used. The Phillips catalyst is a catalyst composed of a main catalyst composed of chromium oxide and a catalyst carrier composed of an oxide such as aluminum. Linear ethylene-α having a polydispersity (Mw / Mn) of 7 to 20
-The olefin copolymer (A-1) characteristically has a melt mass flow rate of 0.2 to 5 g / 10 minutes, preferably 0.5 to 3 g / 10 minutes and a density of 0.90 to 0.96 g.
/ Cm ³ , preferably 0.90 to 0.94 g / cm ³ ,
More preferably, it is desirable that it is 0.90 to 0.93 g / cm ³ . Melt mass flow rate is 0.2g / 1
If it is less than 0 minutes, high-speed workability cannot be obtained, and 5 g / 10
If the amount exceeds the limit, the mechanical properties and heat resistance of the obtained resin composition deteriorate. On the other hand, when the density is less than 0.90 g / cm ³ , the heat resistance decreases, while when it exceeds 0.96 g / cm ³ , the uniform dispersibility of the flame retardant decreases and the flame retardancy, mechanical properties, low temperature brittleness and high speed processing are high. May affect sexuality.

The linear ethylene-α-olefin copolymer (A-1) having a polydispersity (Mw / Mn) of 7 to 20 is specifically ethylene-butene-polymerized by a Phillips catalyst. As one copolymer, GS-650 (Mw / M
n = 15.1, melt mass flow rate = 0.7 g / 1
0 minutes, density = 0.920 g / cm ³ , manufactured by Nippon Unicar), GFX-4355 (Mw / Mn = 13.2, melt mass flow rate = 0.7 g / 10 minutes, density = 0.9
45 g / cm ³ , manufactured by Nippon Unicar Co., Ltd .; GFH-4580H (Mw / Mn = 14.3, melt mass flow rate = 0.7 g / 10 min) as an ethylene-hexene-1 copolymer polymerized with a Phillips catalyst. Density = 0.9
45g / cm ³ , made by Nippon Unicar), prototype (Mw / M
n = 14.3, melt mass flow rate = 0.7 g / 1
0 minutes, density = 0.920 g / cm ³ , made by Nippon Unicar)
Etc. can be mentioned.

On the other hand, a linear ethylene-α-olefin copolymer (A having a polydispersity (Mw / Mn) of 2 to less than 7)
-2) is produced using, for example, a Ziegler-based catalyst or Kaminsky catalyst that has been conventionally used. The Ziegler type catalyst is a catalyst composed of a main catalyst composed of a transition metal compound such as a titanium compound or a vanadium compound, a co-catalyst composed of an organometallic compound such as organoaluminum, and a catalyst carrier composed of an oxide of silicon, titanium, magnesium or the like. Is. Furthermore, the polydispersity (Mw / Mn) is 2 to 7
The linear ethylene-α-olefin copolymer (A-2) having a ratio of less than can also be produced using a recently developed single site catalyst. The single-site catalyst is called in this way because the active sites are of the same type (single-site), and is also referred to as a metallocene or a Kaminsky catalyst from the name of the inventor. Examples of this catalyst include those composed of a transition metal compound having a substituted cyclopentadienyl group, and may further contain an activating cocatalyst. As the cocatalyst, aluminoxane having a high or low degree of polymerization, particularly methylaluminoxane, is preferable. So-called modified aluminoxane is also suitable as a cocatalyst. The linear ethylene-α-olefin copolymer produced using a single site catalyst generally has a polydispersity (Mw / Mn) of 2 to
Since the molecular weight distribution is 3.5 and the width of the molecular weight distribution is very narrow, a linear ethylene having a polydispersity (Mw / Mn) of 3 to less than 7 manufactured by using a Ziegler-based catalyst from the viewpoint of high-speed processability. The -α-olefin copolymer has a slight difference, but is more preferable.

Polydispersity (Mw / Mn) is 2 to less than 7
Linear ethylene-α-olefin copolymer (A-2)
Characteristically has a melt mass flow rate of 0.2 to 10
g / 10 min, preferably 0.5-3 g / 10 min, density
Is 0.86 to 0.96 g / cm^Three, Preferably 0.90
~ 0.94 g / cm^Three, And more preferably 0.90 to 0.
93 g / cm^ThreeIs desirable. Melt mass flow
-Rate is less than 0.2g / 10 minutes, high-speed processability
Resin composition obtained when 10 g / 10 min is not obtained
The mechanical properties and heat resistance of the product are reduced. On the other hand, if the density is
0.86 g / cm ^ThreeIf it is less than 1, the heat resistance is lowered, while on the other hand, it is 0.
96 g / cm^ThreeIf it exceeds, the uniform dispersibility of the flame retardant will decrease.
Flame retardancy, mechanical properties, low temperature brittleness and high speed workability
It may come out.

Linear ethylene-α-olefin copolymer (A-2) having a polydispersity (Mw / Mn) of 2 to less than 7
Specifically, as an ethylene-butene-1 copolymer polymerized with a Ziegler-based catalyst, GRSN-1539 (M
w / Mn = 4.3, melt mass flow rate = 1 g / 1
0 minutes, density = 0.905 g / cm ³ , manufactured by Dow Chemical), GMM-1810 (Mw / Mn = 5.05, melt mass flow rate = 1.0 g / 10 minutes, density = 0.9
18 g / cm ³ , manufactured by Nippon Unicar), GMM-1820
(Mw / Mn = 5.08, melt mass flow rate =
2.0 g / 10 min, density = 0.918 g / cm ³ , manufactured by Nihon Unicar); DFDA-1137 (M) as an ethylene-hexene 1 copolymer polymerized with a Ziegler-based catalyst.
w / Mn = 4.5, melt mass flow rate = 1 g / 1
0 minutes, density = 0.905 g / cm ³ , manufactured by Dow Chemical), GMM-1810H (Mw / Mn = 6.0, melt mass flow rate = 1.0 g / 10 minutes, density = 0.9
18 g / cm ³ , manufactured by Nippon Unicar), GMH-2780
H (Mw / Mn = 5.5, melt mass flow rate =
0.8 g / 10 minutes, density = 0.927 g / cm ³ , manufactured by Nippon Unicar); Escolen 350D as an ethylene-hexene-1 copolymer polymerized with a single-site catalyst.
65 (Mw / Mn = 3.93, melt mass flow rate = 1.03 g / 10 minutes, density = 0.9214 g / c
m ³ , manufactured by Exxon Chemical), Escoren 363C80
(Mw / Mn = 3.90, melt mass flow rate =
2.5 g / 10 minutes, density = 0.9192 g / cm ³ , manufactured by Exxon Chemical), SP-2020 (Mw / Mn =)
4.73, melt mass flow rate = 1.7 g / 10
Min, density = 0.9148 g / cm ³ , manufactured by Mitsui Chemicals; as an ethylene-octene-1 copolymer polymerized with a Ziegler-based catalyst, MORETEC V-0398CN (Mw / M
n = 5.1, melt mass flow rate = 3 g / 10 minutes,
Density = 0.901 g / cm ³ , manufactured by Idemitsu Petrochemical); ethylene-octene-1 polymerized with a single-site catalyst.
As a copolymer, PL-1850 (Mw / Mn = 3.1
7, melt mass flow rate = 3.0 g / 10 minutes, density = 0.902 g / cm ³ , manufactured by Dow Chemical), EG-8
150 (Mw / Mn = 2.2, melt mass flow rate = 0.5 g / 10 minutes, density = 0.865 g / cm ³ , manufactured by Dow Chemical) and the like.

The polydispersity (Mw / Mn) is 7 to 20.
Is a linear ethylene-α-olefin copolymer (A-
1) and the linear ethylene-α-olefin copolymer (A-2) having a polydispersity (Mw / Mn) of 2 to less than 7 are:
You may use it individually by 1 type or in mixture of 2 or more types.

2. Metal Hydroxide (B) In the present invention, a hydrated metal compound is also included as the metal hydroxide (B), and aluminum hydroxide, magnesium hydroxide, calcium hydroxide, barium hydroxide, zirconium hydroxide, basic Examples include magnesium carbonate and hydrotalcite. Among these, magnesium hydroxide having a high melting point can be preferably used. As the magnesium hydroxide, both synthetic magnesium hydroxide produced from seawater or the like and natural ore containing magnesium hydroxide as a main component produced by crushing naturally occurring brucite ore can be preferably used.

The surface of the metal hydroxide (B) has higher fatty acids, higher fatty acid metal salts, higher fatty acid esters, higher fatty acid amides, higher alcohols, hydrogenated oils, and titanate couplings for improving dispersibility and fluidity. It is desirable that the surface is coated with 0.5 to 5% by weight of at least one surface treatment agent selected from agents and silane coupling agents. Specifically, stearic acid, oleic acid, palmitic acid; sodium salts, calcium salts and magnesium salts of these higher fatty acids; methyl esters, propyl esters, butyl esters, octyl esters of these higher fatty acids; amides of these higher fatty acids; Examples thereof include octyl alcohol, myristyl alcohol, stearyl alcohol; hydrogenated tallow oil; isopropyl-tri (dioctyl phosphate) titanate; vinyltriethoxysilane and the like. As the surface treatment method, a wet method,
Either dry type can be used. The average particle diameter of the metal hydroxide (B) is preferably 40 μm or less, and particularly preferably 0.2 to 6 μm, from the viewpoint of dispersibility in resin and flame retardancy. The content of the metal hydroxide (B) is 30 to 180 parts by weight, preferably 70 to 150 parts by weight, and more preferably 80 to 1 part by weight with respect to 100 parts by weight of the base resin.
20 parts by weight. If the content is less than 30 parts by weight, the flame retardancy becomes insufficient, while if it exceeds 180 parts by weight, good high-speed processability cannot be obtained.

3. Other compounding agents The flame-retardant ethylene-based resin composition of the present invention may further contain various compounding agents depending on the purpose of use.
As various compounding agents, stabilizers, antioxidants, ultraviolet absorbers, light stabilizers, antistatic agents, lubricants, processability improvers, fillers, dispersants, coupling agents, copper damage inhibitors, neutralizing agents. , Foaming agents, nucleating agents, anti-foaming agents, colorants, pigments, dyes, carbon black, anti-water tree agents, voltage stabilizers, anti-tracking agents, organic peroxides, crosslinking accelerators, bactericides, antifungal agents, etc. Can be mentioned. Further, the flame-retardant ethylene resin composition of the present invention may be blended with a surface-coated non-halogen flame retardant such as red phosphorus.

When the molded product is used for a covered electric wire used outdoors, it is preferable to add a weathering agent,
As a particularly preferable weather resistance agent, various carbon blacks can be mentioned, and the blending amount thereof is the base resin (A) 10
It is about 1 to 5 parts by weight with respect to 0 parts by weight. Further, in order to obtain heat exposure during molding and stability over time, it is desirable to add an antioxidant. Examples of the antioxidant include phenol-based, phosphorus-based, amine-based, and sulfur-based antioxidants, which may be used alone or as a mixture of two or more thereof, and the compounding amount thereof is 100% by weight of the base resin (A). 0.
It is about 001 to 5 parts by weight. Furthermore, it is desirable to add various lubricants to the flame-retardant ethylene resin composition of the present invention. As the lubricant, known ones such as fatty acid metal salts and fatty acid amides may be used alone or in combination of two or more, and the blending amount thereof is 0.1 to 3 with respect to 100 parts by weight of the base resin (A). It is about part by weight.

Further, the flame-retardant ethylene-based resin composition of the present invention may have an ethylene-based resin other than the linear ethylene-α-olefin copolymer used in the present invention, or other ethylene-based resin, depending on the purpose of use. A small amount of a polyolefin-based resin or an acid-modified product thereof may be added within a range that does not impair the object of the present invention. Examples of these resins and acid-modified products thereof include high-pressure polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, polypropylene, polybutene, and acid-modified products thereof.

4. Preparation of Flame Retardant Ethylene Resin Composition The flame retardant ethylene resin composition of the present invention can be prepared by various preparation methods. For example, a base resin (A), a metal hydroxide (B), and other compounding agents in a solid state such as pellets, granules, and powders, or in a liquid state, a V-type blender, a tumbler blender, a ribbon blender, a rotary blender. Blender with wings or fixed wings,
It can be uniformly mixed with a Henschel mixer or the like to prepare a so-called dry blend or soaking product.

As another preparation method, the base resin (A), the metal hydroxide (B), and other compounding agents, or the dry blended product or soaking product obtained above is used in a Banbury mixer or Buscone kneader. , Mixing roll, intensive mixer, single-screw extruder, twin-screw extruder, multi-screw extruder, static mixer, etc.,
Above the melting temperature of the base resin, for example, 110-220
It can be prepared by melt-kneading at ℃. The resin composition prepared by heating and melting can be preferably granulated into pellets having an average particle diameter of 3 to 7 mm and supplied to a molding machine for molding. In addition, a small amount of other compounding ingredients such as antioxidants and antistatic agents, a high-concentration masterbatch with a linear ethylene-α-olefin copolymer or other ethylene-based resin used in the present invention in advance. It may be manufactured and then blended by dry blending or heat-melt kneading.

5. Production of Coated Electric Wire The coated electric wire of the present invention is a method in which the flame-retardant ethylene-based resin composition of the present invention is directly extrusion-coated on a metal conductor by a known method, for example, using an extrusion molding machine to form an insulating coating layer. Can be manufactured. The coated electric wire of the present invention can also be produced by extrusion-coating a core having a coating insulating layer previously coated with ethylene resin or the like to form a sheath coating layer. The coating can be performed at a linear velocity of over 200 m / min. The conductor is a single wire,
Any stranded wire may be used. A single-screw screw type extruder is generally used as the extruder. An example of the coating process with this extruder is as follows: First, the conductor to be resin-coated is introduced into the crosshead of the extruder, while the resin for coating is fed into the cylinder from the hopper and pushed forward by the screw. While being carried, it is melted by the heat applied from around the cylinder and sent to the crosshead.
At the tip of the crosshead, a die (female type) and a nipple (male type) are provided as a die for coating with a predetermined thickness, and the resin is extruded between these nipples and dies. To be done. After coating, the resin component may be crosslinked with an electron beam or the like. The electric wire may be a single wire, or may be twisted or bundled with tape or the like.

[0030]

The present invention will be described in more detail based on the following examples, but the invention is not intended to be limited to these examples. The samples, physical properties and evaluations used in this specification are based on the following methods.

"Sample" 1. Base resin (A) 1-1. A straight-chain resin having a polydispersity (Mw / Mn) of 7 to 20
Tylene-α-olefin copolymer (A-1) Resin (A-1-1): Linear ethylene-butene-1 copolymer
Combined (Mw / Mn = 15.1, melt mass flow rate
= 0.7 g / 10 minutes, density = 0.920 g / cm ^Three)
(Philips catalyst product) Resin (A-1-2): Linear ethylene-hexene-1
Polymer (Mw / Mn = 14.3, melt mass flow rate)
G = 0.7 g / 10 minutes, density = 0.920 g / cm^Three)
(Filps type catalyst product)

1-2. Polydispersity (Mw / Mn) is 2-7
Less than linear ethylene-α-olefin copolymer (A-
2) Resin (A-2-1): Linear ethylene-butene-1 copolymer
Combined (Mw / Mn = 4.3, melt mass flow rate =
1 g / 10 minutes, density = 0.905 g / cm^Three) (Chigue
Ra-based catalyst product) Resin (A-2-2): Linear ethylene-hexene-1
Polymer (Mw / Mn = 4.5, melt mass flow rate
= 1 g / 10 minutes, density = 0.905 g / cm^Three) (Qi
(Gura type catalyst product) Resin (A-2-3): both linear ethylene-octene-1
Polymer (Mw / Mn = 5.1, melt mass flow rate
= 3 g / 10 minutes, density = 0.901 g / cm^Three) (Qi
(Gura type catalyst product) Resin (A-2-4): both linear ethylene-octene-1
Polymer (Mw / Mn = 2.2, melt mass flow rate
= 0.5 g / 10 minutes, density = 0.865 g / cm ^Three)
(Single-site catalyst product)

2. Metal hydroxide (B) (hereinafter, Mg (O
H) Also called ₂ . ) Mg (OH) ₂ 1: surface-coated synthetic magnesium hydroxide,
Magushizu (R) N-4 (Konoshima Chemical Co.) Mg _(OH) 2 2: surface coating natural ore-derived magnesium hydroxide, Magushizu (registered trademark) (manufactured by Konoshima Chemical) N-1, where the mean particle by air classification The diameter is about 5 μm.

3. Other compounding agents Antioxidant: Tetrakis [methylene-3- (3 ', 5'
-Di-t-butyl-4'-hydroxyphenyl) propionate] methane, Irganox® 101
0 (Ciba Specialty Chemicals)

"Evaluation" 1. Melt mass flow rate (hereinafter, also referred to as MFR) Conducted in accordance with JIS K6922-2, temperature 190 ° C,
The load was measured at 2.16 kg.

2. Mechanical characteristics 2-1. Tensile breaking stress It was performed according to JIS C3005. Tension speed is 200
m / min and 10 MPa or more was passed. 2-2. Tensile fracture strain It was performed based on JIS C3005. 400% or more was passed.

3. Low temperature characteristics 3-1. Low temperature brittleness (F0) The low temperature characteristics were evaluated by the low temperature brittleness (F0) of JIS K7216. A type test piece was used. The definition of fracture was that a crack was generated in the test piece, and -10 ° C or less was passed.

4. Flame retardance 4-1. The oxygen index flame retardancy was evaluated by the oxygen index of JIS K7201-1995. The No. A-1 test piece was used. Oxygen index 2
Two or more were passed.

5. High-speed processability 5-1. An extruded wire coating device with a surface smoothness and a critical linear velocity of 50 mm and L / D = 25 is used to form a coating layer on a copper conductor core wire with a diameter of 0.4 mm to a coating thickness of 0.625 mm. Manufactured an electric wire. By varying the linear velocity and measuring the surface smoothness of the produced coated electric wire with a surface roughness meter, the maximum linear velocity at which a coated electric wire with a surface smoothness of 0.5 μm or less can be formed is defined as the critical linear velocity with surface smoothness. did. Those with a critical linear velocity exceeding 200 m / min were regarded as acceptable. 5-2. With a critical drawdown property with a surface smoothness of 50 mm in diameter and L / D = 25, an extruded electric wire coating device is used to form a coating layer on a copper conductor core wire with a diameter of 0.4 mm to a coating thickness of 0.625 mm. A coated electric wire was manufactured, drawn off at a critical linear velocity with surface smoothness, the outer diameter at which surface smoothness was obtained was measured, and the critical drawdown ratio with surface smoothness was calculated by the following formula. As a critical drawdown property with surface smoothness, a critical drawdown ratio with surface smoothness of 2% or more was passed. Critical drawdown ratio with surface smoothness = (outer diameter of wire with surface smoothness / diameter of die) x 100 (%)

6. Comprehensive evaluation mechanical properties: tensile fracture stress of 10 MPa or more, tensile fracture strain of 400% or more, and low temperature brittleness (F0)
Those having a temperature of −10 ° C. or less were accepted. Regarding the flame retardancy, those having an oxygen index of 22 or more were accepted. Regarding high-speed processability, a material having a surface smoothness critical linear velocity of more than 200 m / min and a surface smoothness critical drawdown ratio of 2% or more was regarded as acceptable. It should be noted that the case of passing was represented by ◯, and the case of failing was represented by x.

Examples 1 to 5 As a base resin (A), a linear ethylene-butene-1 copolymer (resin A-1) was used.
-1) (Mw / Mn = 15.1, MFR = 0.7 g / 1
0 minutes, density 0.920 g / cm ³ ) and linear ethylene-octene-1 copolymer (resin A-2-3) (Mw / M
n = 5.1, MFR = 3 g / 10 min, density 0.901 g
/ Cm ³ ) and the composition specified in Table 1 (% by weight)
To 100 parts by weight of the base resin (A) described above, 100 parts by weight of Mg (OH) ₂ as a metal hydroxide (B) and 0.2 parts by weight of an antioxidant of another compounding agent were added to a Banbury mixer. Was melt-kneaded at about 210 ° C. for 6 minutes, and then granulated to an average particle size of about 4 mm to obtain a flame-retardant ethylene-based resin composition of the present invention, which was evaluated by the above-mentioned “evaluation” method. 15.1 of Mw / Mn constituting the base resin (A)
Resin (A-1-1) and Mw / Mn of 5.1 (A
The composition ratio of (2-3) is 10 to 90 parts by weight and 9 respectively.
In these Examples 1-5 which changed into 0-10 weight,
As is clear from the results shown in Table 1, the resin (A-1-
It was found that the mechanical properties, including low temperature properties, decreased as the composition and composition ratio of 1) increased, but it showed excellent mechanical properties and satisfied good high-speed processability and flame retardancy. Met.

[Comparative Examples 1 to 4] In Comparative Examples 1 to 4, flame retardance was the same as in Example 1 except that one kind of base resin (A) was used as shown in Table 1. An ethylene resin composition was prepared and evaluated in the same manner. The results are shown in Table 1, but the base resin (A) made of the resin (A-1-1)
, The mechanical properties, especially low temperature brittleness, become poor, while W
Ethylene-butene-1 copolymer having a w / Mn of 4.3 to 5.1 (Resin A-2-1) (Mw / Mn = 4.3, MFR
= 1 g / 10 minutes, density 0.905 g / cm ³ ), ethylene-hexene-1 copolymer (resin A-2-2) (Mw /
Mn = 4.5, MFR = 1 g / 10 min, density 0.905
g / cm ³ ), and an ethylene-octene-1 copolymer (resin A-2-3) (Mw / Mn = 5.1, MFR = 3).
Comparative Examples 2 to 4 prepared from the base resin (A) consisting only of g / 10 minutes and a density of 0.901 g / cm ³ ) had good mechanical properties and flame retardancy, but satisfied high-speed processability. It became clear that not.

[0043]

[Table 1]

[Examples 6 to 9] The flame retardancy of the present invention was obtained in the same manner as in Example 1 except that the type of resin constituting the base resin (A) and the constitution thereof were changed as shown in Table 2. An ethylene resin composition was obtained and evaluated in the same manner as in Example 1.
The results are shown in Table 2, and the ethylene-octene-1 copolymer (resin A
-2-4) (Mw / Mn = 2.2, MFR = 0.5 g /
Example 9 using 10 minutes and a density of 0.865 g / cm ³ ) was slightly inferior in heat resistance. However, including this, these flame-retardant ethylene-based resin compositions have excellent mechanical properties. ,
It showed good flame retardancy and high-speed processability.

[Example 10, Comparative Examples 5 and 6] Example 10
It was replaced by Mg _{(OH) 2} 1 a is a surface coating natural ore-derived magnesium hydroxide Mg _{(OH) 2 2} As is
Further, as Comparative Examples 5 and 6, Mg (OH) ₂ 1 of Example 1 was used.
A flame-retardant ethylene-based resin composition was obtained and evaluated in the same manner as in Example 1 except that the composition and blending amount of the above was changed to 15 parts by weight and 200 parts by weight, respectively. The results are shown in Table 2, and it was confirmed that good high-speed processability can be ensured even if the natural ore-derived magnesium hydroxide is used. But,
If the blending amount of the metal hydroxide (B) is less than the lower limit value and more than the upper limit value of the present invention, the flame retardancy becomes insufficient if it is less than the lower limit value, and if it exceeds the upper limit value, the surface smoothness is high among the high-speed processability. Although it passed the critical linear velocity, the drawdown property with surface smoothness was rejected, resulting in poor high-speed workability, and insufficient tensile fracture stress and mechanical properties. .

[0046]

[Table 2]

[0047]

As described in detail above, the flame-retardant ethylene-based resin composition of the present invention comprises a base resin (A) made of an ethylene-based resin and a metal hydroxide (B). (A) is a specific polydispersity (Mw / M)
n), MFR and a specific blending ratio of ethylene with density
Since it is composed of the α-olefin copolymers (A-1) and (A-2), it does not contain halogen, is safer, and has a smaller environmental load. Moreover, it has excellent mechanical properties, low temperature properties, and good high-speed processability. Further, a coated electric wire having an insulating multi-layer and / or a sheath coating layer using the flame-retardant ethylene-based resin composition of the present invention has good insulation properties and electrical properties of the ethylene-based resin itself, Sometimes it can be incinerated without generating pollutant gas, etc.
Moreover, as a coating method, a high linear velocity, for example, 200
There is an effect that it is possible to provide a manufacturing method for processing a cable at a linear velocity exceeding m / min. The produced coated electric wire can be widely used as an electric wire for automobiles, communication, and electric power.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ identification code FI theme code (reference) H01B 3/44 H01B 3/44 P 7/295 13/14 Z 13/14 7/34 BF term (reference) ) 4J002 BB05W BB05X DE066 DE076 DE086 DE096 DE146 DE236 FB086 FB106 FB216 FB236 FB246 FB256 FD136 GQ01 5G303 AA06 AA08 AB20 BA12 CA09 CA11 5G305 AA02 AB15 AB02 AB02 AB15 AB02 AB15 AB02 AB15 AB02 AB12 JC09

Claims (5)

[Claims] 1. A flame-retardant ethylene-based resin composition obtained by mixing 30 to 180 parts by weight of a metal hydroxide (B) with 100 parts by weight of a base resin (A). Polydispersity (Mw / expressed as a ratio of weight average molecular weight (Mw) to number average molecular weight (Mn))
Mn) is 7 to 20, melt mass flow rate is 0.2 to
5g / 10 minutes, and density 0.90 to 0.96g / cm
³ linear ethylene-α-olefin copolymer (A-
1) 95 to 5% by weight and polydispersity (Mw / Mn) of 2
Less than 7, melt mass flow rate 0.2 to 10 g / 1
0 minutes, and a linear ethylene-α-olefin copolymer (A-2) 5 to 9 having a density of 0.86 to 0.96 g / cm ³
A flame-retardant ethylene-based resin composition comprising 5% by weight. 2. A linear ethylene-α-olefin copolymer (A-1) is polymerized with a Phillips catalyst, while a linear ethylene-α-olefin copolymer (A-) is used. The flame-retardant ethylene-based resin composition according to claim 1, wherein 2) is polymerized with a Ziegler-based catalyst. 3. The metal hydroxide (B) is selected from the group consisting of higher fatty acids, higher fatty acid metal salts, higher fatty acid esters, higher fatty acid amides, higher alcohols, hardened oils, titanate coupling agents or silane coupling agents. The flame-retardant ethylene-based resin composition according to claim 1, which is magnesium hydroxide whose surface is coated with one or more types of surface treatment agents. 4. An insulating coating layer formed from the flame-retardant ethylene-based resin composition according to claim 1, and /
Alternatively, a coated electric wire having a sheath coating layer. 5. The flame-retardant ethylene-based resin composition according to any one of claims 1 to 3 is extruded on a metal conductor at a linear velocity of more than 200 m / min and coated as an insulating coating layer and / or a sheath coating layer. The method for producing a covered electric wire according to claim 4, wherein the coated electric wire is formed.