JP2007277530A - Flame-retardant resin composition and insulated wire coated with the resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flame-retardant resin composition excellent in abrasion resistance and well-balanced in many properties such as flame retardance and mechanical properties, and insulated wire coated with the resin composition. <P>SOLUTION: The flame-retardant resin composition comprises 100 pts.mass resin mixture consisting of 40-90 mass% polypropylene-based resin, 5-20 mass% ethylenic copolymer, 5-20 mass% modified styrene-based thermoplastic elastomer and 0-20 mass% modified polyolefin, 40-150 pts.mass magnesium hydroxide and 1-20 pts.mass clay mineral, and the resin composition is most suitable for insulating coating material of electric wire installed in automobiles and electrical and electronic appliances and components, etc., for the automobiles, etc. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a flame retardant resin composition and an insulated wire coated with the resin composition. More specifically, the present invention relates to a flame retardant resin composition used for automobiles, electrical / electronic devices, and the like, and an insulated wire coated with the resin composition.

Insulating coating materials for components such as automobiles, electrical / electronic devices, and insulated wires installed in these components include various materials such as flame resistance and wear resistance in addition to heat resistance, cold resistance, and moisture resistance. Characteristics are required. Polyvinyl chloride (PVC) resins and polyolefin resins containing halogen-based flame retardants containing bromine (Br) atoms or chlorine (Cl) atoms in the molecule are widely used as resin materials constituting them. It had been. On the other hand, when products using such materials are discarded without appropriate treatment, various problems have occurred. For example, when these products are disposed of in landfills, There is a problem that lead compounds, etc. will be eluted as phosphorus compounds, plasticizers and heavy metal stabilizers contained in the product, while corrosive halogen gases and dioxins will be generated when discarded by incineration. There was a problem.

For this reason, non-halogen flame retardant resin compositions that do not generate harmful heavy metals or corrosive halogen-based gases have been studied and some have been put into practical use. Non-halogen flame retardant resin compositions that have been studied or put into practical use are widely known to use a polyolefin resin as a base polymer and are filled with a large amount of metal hydrates such as magnesium hydroxide and aluminum hydroxide. In addition, as the base polymer of the resin composition, an ethylene copolymer that easily disperses a large amount of metal hydrate has been used.

On the other hand, since the mechanical properties and heat resistance of such a halogen-free flame retardant resin composition are lower than those of currently used polyvinyl resins, the halogen-free flame retardant properties equivalent to polyvinyl chloride resins are used. Development of materials is expected. And in order to solve such a problem, the resin composition which uses the polypropylene excellent in a mechanical characteristic and heat resistance as a base polymer (for example, refer patent document 1), the difficulty which uses an ethylene-type copolymer as a base polymer. A method of crosslinking a flammable resin composition by chemical crosslinking or electron beam crosslinking has been studied (for example, see Patent Document 2).

JP 2001-354826 A ([Claim 1], [0007]) JP 2002-332385 A ([Claim 3], [0019])

However, it has been difficult for the above-described conventional resin compositions to have various properties such as flame retardancy, mechanical properties, heat resistance, and cold resistance in a well-balanced manner. Furthermore, an insulated wire coated with a flame retardant resin composition that has been studied or put into practical use is inferior in wear resistance compared to an insulated wire that has been coated with a conventional polyvinyl chloride resin. There was also a need for improvement.

The present invention has been made in view of the above problems, is excellent in wear resistance, and is further flame retardant,
An object of the present invention is to provide a flame retardant resin composition balanced in mechanical properties and an insulated wire coated with the resin composition.

In order to solve the above problems, the flame retardant resin composition of the present invention comprises (a) 40 to 90% by mass of a polypropylene resin, (b) 5 to 20% by mass of an ethylene copolymer, and (c) a modification. 5-20% by mass of a styrenic thermoplastic elastomer, and (d) 0-20% by mass of a modified polyolefin.
(E) 40-150 mass parts of magnesium hydroxide and (f) 1-20 mass parts of clay minerals are contained with respect to 100 mass parts of resin mixture which consists of.

In the flame-retardant resin composition of the present invention, the (e) magnesium hydroxide is preferably not subjected to surface treatment.

In the flame-retardant resin composition of the present invention, the mass ratio of (b) the ethylene copolymer and (c) the modified styrene thermoplastic elastomer is ethylene copolymer / modified styrene thermoplastic elastomer = It is preferably 2/1 to 1/2.

The insulated wire of the present invention is characterized in that a conductor is extrusion coated with the flame retardant resin composition of the present invention.

The flame retardant resin composition of the present invention uses a polypropylene resin as a base polymer,
In addition, a resin mixture comprising a specific amount of an ethylene copolymer, a modified styrene thermoplastic elastomer and a modified polyolefin has a constitution containing specific amounts of magnesium hydroxide and clay minerals respectively. Excellent wear resistance in addition to cold resistance,
The flame retardancy and mechanical properties are also good, and the flame retardant resin composition has a good balance of these properties.

Moreover, the flame-retardant resin composition of this invention can improve the abrasion resistance of the said resin composition by employ | adopting the magnesium hydroxide by which surface treatment is not given as magnesium hydroxide.

Further, in the flame retardant resin composition of the present invention, the mass ratio of the ethylene copolymer and the modified styrene thermoplastic elastomer is such that the ethylene copolymer / modified styrene thermoplastic elastomer = 2/1 to 1. Therefore, the abrasion resistance of the resin composition can be further improved.

And since the insulated wire of the present invention is formed by extrusion-coating the above-mentioned flame-retardant resin composition of the present invention on a conductor, it enjoys the effects exhibited by the above-described resin composition of the present invention, and has heat resistance and cold resistance. In addition, the insulated wire has a well-balanced wear resistance, flame retardancy, and mechanical properties.

Hereinafter, the flame retardant resin composition of the present invention will be described. The flame-retardant resin composition of the present invention (hereinafter sometimes simply referred to as “resin composition”) is (a) polypropylene-based resin 40 to 90.
100 parts by mass of a resin mixture comprising 5% by mass, (b) 5 to 20% by mass of an ethylene copolymer, (c) 5 to 20% by mass of a modified styrene thermoplastic elastomer, and (d) 0 to 20% by mass of a modified polyolefin. (E) 40 to 150 parts by mass of magnesium hydroxide, and (f)
It contains 1 to 20 parts by mass of clay mineral.

(A) Polypropylene resin:
The polypropylene constituting the flame retardant resin composition of the present invention serves as a base polymer of the resin composition, and makes the mechanical properties, heat resistance and cold resistance of the resin composition good. Examples of usable polypropylene resins include those obtained by polymerizing only propylene, ethylene, 1
-What copolymerized (alpha) -olefins, such as butene, and propylene, etc. are mentioned. Specifically, for example, homopolypropylene, block polypropylene, random polypropylene,
A propylene-ethylene random copolymer, a propylene-butene random copolymer, etc. are mentioned.

In addition, as such a polypropylene resin, the hardness (HRR) is considered in consideration that the resin composition of the present invention is used as an insulating coating material for a member that requires wear resistance or an insulated wire.
Is preferably 65 or more and a flexural modulus of 1000 MPa or more.

In the present invention, these polypropylenes have a melt flow rate (MFR) defined in JIS K7210 of 1 from the viewpoint of improving the kneadability of the resin composition.
It is preferably 0.0 g / 10 min or less (230 ° C., 2.16 kgf load).

(B) Ethylene copolymer:
The ethylene copolymer constituting the flame retardant resin composition of the present invention improves the mechanical properties and wear resistance of the resin composition by using in combination with (c) a modified styrene thermoplastic elastomer described later. Have a function. As an ethylene-based copolymer that can be used in the present invention,
Examples include ethylene / vinyl acetate copolymers, ethylene / acrylic acid copolymers, ionomers, ethylene / methyl acrylate copolymers, ethylene / ethyl acrylate copolymers, and ethylene / butyl acrylate copolymers.

In the present invention, these ethylene copolymers have a melt flow rate (MFR) defined in JIS K7210 of 10.0 g / 10 from the viewpoint of improving the kneadability of the resin composition, similarly to polypropylene resins. It is preferable that it is less than a minute (190 degreeC, 2.16kgf load). Examples of such ethylene-based copolymers include “Evaflex”, “Nuclele”, “High Milan” (all manufactured by Mitsui DuPont Polychemical Co., Ltd.), “Lotril” (manufactured by Atofina), and the like.

(C) Modified styrenic thermoplastic elastomer:
A modified styrenic thermoplastic elastomer that constitutes the flame-retardant resin composition of the present invention and improves the mechanical properties and abrasion resistance of the resin composition by using in combination with the (b) ethylene copolymer, A styrenic thermoplastic elastomer is modified with an unsaturated carboxylic acid and / or a derivative thereof.

Styrenic thermoplastic elastomers that can be used include styrene-butadiene-styrene block copolymers (SBS) and styrene-isoprene-styrene block copolymers (S
IS), styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-ethylene-propylene-styrene block copolymer (SEPS), and the like.
Examples of the unsaturated carboxylic acid include maleic acid, itaconic acid, and fumaric acid. 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 can be mentioned.

In the present invention, these modified styrenic thermoplastic elastomers, like polypropylene resins and ethylene copolymers, improve the kneadability of the resin composition, so that the melt flow rate defined in JIS K7210 is used. (MFR) is 10.0 g / 10
It is preferable that it is below a minute (230 degreeC, 2.16kgf load). Examples of such a modified styrene-based thermoplastic elastomer include “modified DYNARON” (manufactured by JSR Corporation), “Tough Tech M” (manufactured by Asahi Kasei Corporation), “Clayton FG1901X” (manufactured by Kraton Polymer Co., Ltd.), and the like. is there.

(D) Modified polyolefin:
The modified polyolefin is added to the resin composition of the present invention as necessary, and improves the dispersibility of the resin composition of (e) magnesium hydroxide and (f) inorganic filler, which are non-resin components described later, and further mechanically. Has a function to improve properties and wear resistance.

The modified polyolefin is obtained by modifying a polyolefin resin with an unsaturated carboxylic acid and / or a derivative thereof. Examples of the polyolefin resin that can be used include polypropylene and polyethylene. Examples of the unsaturated carboxylic acid include maleic acid, itaconic acid, and fumaric acid. Examples of the unsaturated carboxylic acid derivative include maleic acid monoester, maleic acid diester, maleic anhydride, itaconic acid monoester, There are itaconic acid diester, itaconic anhydride, fumaric acid monoester, fumaric acid diester and the like.

In the present invention, these modified polyolefins have a melt flow rate as defined in JIS K7210 of 10.0 g / 10 min (in terms of improving the kneadability of the resin composition in the same manner as polypropylene resins and the like. 190 ° C., 2.16 kgf load) or less. Examples of such modified polyolefins include “Polybond” (manufactured by Uniroyal Chemical Co., Ltd.), “Adtex” (manufactured by Nippon Polyethylene Co., Ltd.), “Orebak” (manufactured by Atofina), and the like.

(E) Magnesium hydroxide:
Magnesium hydroxide that constitutes the flame-retardant resin composition of the present invention improves the flame retardancy of the resin composition and improves the wear resistance. In addition, examples of magnesium hydroxide used in the present invention include those that have been surface-treated with a fatty acid, a silane coupling agent, or the like, and those that have not been surface-treated, but are not subjected to surface treatment. It is preferable to employ magnesium, whereby the wear resistance of the resin composition can be further improved. As magnesium hydroxide not subjected to surface treatment, for example, “Magnifine H7
”(Manufactured by Albemarle Co., Ltd.),“ Kisuma 5 ”(manufactured by Kyowa Chemical Industry Co., Ltd.) and the like. As the surface-treated magnesium hydroxide, for example, surface treatment with a silane coupling agent or the like is performed. Kisuma 5L "(manufactured by Kyowa Chemical Industry Co., Ltd.).

Magnesium hydroxide has a good dispersibility in the resin mixture.
Those having an average particle diameter in the range of ˜1.5 μm and having almost no aggregation are preferred. The average particle size is particularly preferably about 0.5 to 1.0 μm.

(F) Clay mineral:
The clay mineral constituting the flame retardant resin composition of the present invention has a function of improving the wear resistance by being contained in the resin composition. Examples of the clay mineral that can be used in the present invention include kaolinite, calcined kaolinite, montmorillonite, sepiolite, talc, mica and the like, and it is particularly preferable to use calcined kaolinite. These clay minerals may be used alone or in combination of two or more. Further, like magnesium hydroxide, it is preferable to employ a clay mineral that is not subjected to a surface treatment such as a fatty acid or a silane coupling agent or an organic treatment such as an alkyl ammonium salt, an alkyl sulfonium salt, or an alkyl phosphonium salt. . By not subjecting the clay mineral to a surface treatment such as an organic treatment, the wear resistance of the resulting resin composition can be further improved.

  In the present invention, the clay mineral preferably has an average particle size of 10 μm or less, has an average particle size in the range of 0.3 to 2.0 μm, and has almost no aggregation. It is particularly preferable to do this. Examples of such clay minerals include “SATINTONE”, “TRANSLINK” (manufactured by ENGELHARD), “PANGEL” (manufactured by TOLSA), and the like.

Next, the content of each component in the flame retardant resin composition of the present invention will be described.
The content of (a) polypropylene in the resin composition is the entire resin component, that is,
40 to 9 with respect to the entire resin mixture comprising (a) polypropylene resin, (b) ethylene copolymer, (c) modified styrene thermoplastic elastomer, and (d) modified polyolefin.
0% by mass. When the content of the polypropylene resin is less than 40% by mass, the wear resistance and heat resistance of the resin composition may be lowered. On the other hand, when the content exceeds 90% by mass, the mechanical properties of the resin composition are reduced. And cold resistance may decrease. The content of the polypropylene resin is preferably 70 to 80% by mass with respect to the entire resin mixture.

(B) The ethylene copolymer and the (c) modified styrene thermoplastic elastomer are used in combination with polypropylene, but mechanical properties and wear resistance are improved by using them together. The content of the ethylene copolymer is 5 to 20% by mass with respect to the entire resin mixture, and the content of the modified styrene thermoplastic elastomer is also 5 to 20% by mass with respect to the entire resin mixture.
It is. The content of ethylene copolymer and modified styrene thermoplastic elastomer is 5% by mass
If it is smaller, the mechanical properties and cold resistance may be lowered. On the other hand, if the content exceeds 20% by mass, the wear resistance and heat resistance may be lowered. The content of the ethylene copolymer or the modified styrene thermoplastic elastomer is preferably 5 to 10% by mass with respect to the entire resin mixture.

The mass ratio of the ethylene copolymer to the modified styrene thermoplastic elastomer is preferably ethylene copolymer / modified styrene thermoplastic elastomer = 2/1 to 1/2, and is substantially equivalent (1 / 1) is particularly preferred. Wear resistance is further improved by making both within the range of this mass ratio.

The total content of the ethylene copolymer and the modified styrene thermoplastic elastomer is preferably 10 to 40% by mass with respect to the entire resin mixture. When the total content is less than 10% by mass, the mechanical properties and cold resistance of the resin composition may be lowered.
When it exceeds mass%, the abrasion resistance and heat resistance of the resin composition may be lowered. The total content of the ethylene copolymer and the modified styrene thermoplastic elastomer is particularly preferably 10 to 20% by mass.

The content of (d) the modified polyolefin in the resin composition is 0-2 in the entire resin mixture.
0% by mass. When the content of the modified polyolefin exceeds 20% by mass, the fluidity of the resin composition is lowered, and a problem may occur in molding processability. The content of the modified polyolefin is preferably 5 to 10% by mass with respect to the entire resin mixture. In the flame-retardant resin composition of the present invention, depending on the content of the polypropylene resin, the ethylene copolymer, and the modified styrene thermoplastic elastomer, a configuration not containing the modified polyolefin may be employed. However, by containing the modified polyolefin, the dispersibility of the magnesium hydroxide is improved as compared with the flame retardant resin composition not containing the modified polyolefin, which leads to improvement in wear resistance and flame retardancy. On the other hand, by not containing the modified polyolefin, each characteristic is slightly inferior to what is contained, but still excellent mechanical properties such as tensile properties, wear resistance and flame retardancy can be maintained.

The content of (e) magnesium hydroxide in the resin composition is 40 to 150 parts by mass with respect to 100 parts by mass of the resin mixture. If the content of magnesium hydroxide is less than 40 parts by mass, sufficient flame retardancy cannot be imparted to the resin composition, while if it exceeds 150 parts by mass, the mechanical properties and cold resistance of the resin composition are not achieved. The specific gravity is adversely affected and the specific gravity is increased. It is preferable that content of magnesium hydroxide shall be 60-120 mass parts with respect to 100 mass parts of resin mixtures.

The content of (f) clay mineral in the resin composition is based on 100 parts by mass of the resin mixture.
1 to 20 parts by mass. When the content of the clay mineral is less than 1 part by mass, the abrasion resistance of the resin composition is not improved. On the other hand, when it exceeds 20 parts by mass, the mechanical properties of the resin composition are deteriorated. The content of the clay mineral is preferably 1 to 10 parts by mass with respect to 100 parts by mass of the resin mixture.

It should be noted that various resin components and rubber components other than those described above and various additives may be appropriately added to the resin composition of the present invention as necessary within the range not hindering the object and effect of the present invention. it can. As additives, conventionally known ones can be used, for example, lubricants, antioxidants, light stabilizers, process oils, silicon oils, ultraviolet absorbers, carbon black, dispersants, pigments, dyes, antiblocking agents. Agents, crosslinking agents, crosslinking aids, etc.
Depending on the application, conventionally used flame retardant aids such as red phosphorus, polyphosphoric acid compounds, zinc hydroxystannate, zinc stannate, zinc borate, calcium carbonate, hydrotalcite, and antimony oxide may be added. .

The flame-retardant resin composition of the present invention is obtained by melt-kneading the above-described components and additives added as necessary with a conventionally known kneading apparatus such as a twin-screw kneading extruder, a Banbury mixer, a kneader, or a roller. It can manufacture more simply. Moreover, when a twin-screw extruder is used, a process can be implemented continuously.

In the production of a flame retardant resin composition, a polypropylene resin, magnesium hydroxide, and clay mineral (and additives if necessary) are previously melt-kneaded to obtain a melt-kneaded product, and then the melt-kneaded product. The remaining materials (ethylene copolymer, modified styrene thermoplastic elastomer, modified polyolefin) may be further melt-kneaded. Moreover, it is preferable to set as kneading | mixing temperature below the decomposition temperature of component (e) magnesium hydroxide (for example, 340 degrees C or less).

Moreover, you may make it perform the crosslinking process as needed for the flame-retardant resin composition of this invention.
As a crosslinking method, a conventional electron beam irradiation crosslinking method or chemical crosslinking method can be employed.
In the case of the electron beam irradiation cross-linking method, the cross-linking can be performed by irradiating an electron beam by a conventional method after molding the flame retardant resin composition of the present invention. On the other hand, in the case of the chemical crosslinking method, an organic peroxide or the like may be added to the resin composition as a conventionally known crosslinking agent, and after the molding, heat treatment may be performed by a conventional method for crosslinking.

The flame retardant resin composition of the present invention uses a polypropylene resin as a base polymer,
In addition, a resin mixture comprising a specific amount of an ethylene copolymer, a modified styrene thermoplastic elastomer and a modified polyolefin has a constitution containing specific amounts of magnesium hydroxide and clay minerals respectively. Excellent wear resistance in addition to cold resistance,
The flame retardancy and mechanical properties are also good, and the flame retardant resin composition has a good balance of these properties. And it is easy to recycle even after disposal, and even if it is disposed of such as buried, it does not cause environmental pollution problems due to lead-based compounds or phosphorus compounds, and even if it is incinerated, harmful halogen gas, dioxin, etc. It is environmentally friendly.

Insulated wires obtained by extrusion-coating the flame-retardant resin composition of the present invention on conductors and optical fibers such as copper wires, tin-plated copper wires, and aluminum wires have mechanical properties such as flame resistance, wear resistance, and tensile properties. It can be widely used as an electric wire having characteristics and adaptability to the environment. In particular, when an electric wire extrusion-coated with the flame retardant resin composition of the present invention is used as an electric wire disposed in an automobile or electronic device that requires high wear resistance, flame resistance, mechanical properties, etc. The effect can be maximized. Such an insulated wire can be easily obtained by extrusion-coating the resin composition of the present invention on the outer periphery of the conductor using a known extrusion molding method.

In addition, in the insulated wire of this invention, the thickness of insulation coating material does not have a restriction | limiting in particular, It can form as desired thickness. Further, the insulated wire has no problem even if the insulating layer has a multi-layer structure, such as separately providing an intermediate layer between the insulating coating material made of the resin composition of the present invention and the conductor.

Moreover, the flame-retardant resin composition of this invention can provide the resin molding which enjoys the above-mentioned outstanding effect by setting it as a resin molding. There is no particular limitation on the shape of the resin molded body, for example, a power plug, a connector, a sleeve, a box, a tape base material, a tube,
A sheet etc. can be mentioned. These resin moldings can be obtained by molding the resin composition of the present invention by a conventionally known molding method such as an extrusion molding method or an injection molding method.

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

[Examples 1-5, Comparative Examples 1-6]
Table 1 and Comparative Examples 1 to 5 show the configurations (materials used and contents) of the flame-retardant resin compositions of Examples 1 to 5.
Table 2 shows the composition (materials used and content) of the flame retardant resin composition No. 6.

The details of the materials used are as follows. Melt flow rate (MFR
) Was measured under the following temperature and load conditions in accordance with JIS K7210. Here, the contents in Table 1 and Table 2 are shown as parts by mass when the entire resin mixture is 100 parts by mass (for each of the resin materials constituting the resin mixture consisting of (1) to (4)). This is the same as the content (mass%) when the entire resin mixture is 100 mass%.)

(1) Polypropylene (polypropylene resin)
Product name: E-200GP (manufactured by Prime Polymer Co., Ltd.)
MFR: 2.0 g / 10 min (230 ° C., 2.16 kgf load)

(2) Ethylene / vinyl acetate copolymer (ethylene copolymer):
Product name: Everflex V527-4 (Mitsui DuPont Polychemical Co., Ltd.)
MFR: 0.7 g / 10 min (190 ° C., 2.16 kgf load)

(3) Modified styrenic thermoplastic elastomer Product name: Kraton FG1901X (manufactured by Kraton Polymer Co., Ltd.)
MFR: 6.4 g / 10 min (230 ° C., 2.16 kgf load)

(4) Modified polyolefin Product name: Adtex L6100M (manufactured by Nippon Polyethylene Co., Ltd.)
MFR: 1.1 g / 10 min (190 ° C., 2.16 kgf load)

(5) Magnesium hydroxide A
Product Name: Kisuma 5L (Kyowa Chemical Industry Co., Ltd.)
Surface treatment: Yes (Surface treatment with silane coupling agent)
Average particle size: 0.8μm

(6) Magnesium hydroxide B
Product Name: Magnificin H7 (Albemarle)
Surface treatment: None Average particle size: 1.0 μm

(7) Clay mineral A
Product name: Satinton SP33 (manufactured by Engelhard)
Surface treatment: None Average particle size: 1.4 μm

(8) Clay mineral B
Product Name: Nanofil 5 (Zudchemy)
Surface treatment: Yes (Organized with alkyl ammonium salt)
Average particle size: 8.0 μm

(9) Antioxidant Irganox 1010 (manufactured by Ciba Specialty Chemicals)

(10) Lubricant Neowax ACL (manufactured by Yasuhara Chemical Co., Ltd.)

(Composition of resin composition: Examples)

(Composition of resin composition: Comparative example)

[Test Example 1]
The flame retardant resin compositions of Examples 1 to 5 and Comparative Examples 1 to 6 were subjected to a general-purpose extruder for producing electric wires using a conventionally known extrusion condition. An insulated wire was manufactured by continuously extruding the outer periphery of an 85 mm annealed copper wire at a thickness of 0.2 mm as an insulating coating material. The obtained insulated wires were compared and evaluated for “tensile properties”, “flame resistance” and “abrasion resistance” according to the following criteria. The results are shown in Table 3.

(Tensile properties)
The tensile strength (MPa) and tensile elongation (%) of the insulation coating material of the obtained insulated wire were measured according to JIS.
Based on C3005, measurement was performed at a marked line of 50 mm and a tensile speed of 200 mm / min. The tensile strength was 16 MPa or more, and the tensile elongation was 125% or more.

(Flame retardance)
A horizontal combustion test specified in JIS C3005 was carried out to confirm flame retardancy. If the flame disappeared within 15 seconds, it was considered acceptable.

(Abrasion resistance)
A load of 7 N was applied to the blade with a piano wire of φ0.45 mm attached to the tip, the wire surface was reciprocated at 60 times / minute, and the number of reciprocations until the blade penetrated the coating and contacted the conductor was measured. The test was accepted after 150 times.

(result)

From the results shown in Table 3, the insulated wires obtained by extrusion coating the resin compositions shown in the examples of the present invention exhibited excellent tensile properties, wear resistance and flame retardancy. In particular, Example 2 using magnesium hydroxide that had not been surface-treated was superior in wear resistance to Example 1 containing the same amount of surface-treated magnesium hydroxide. In addition, Example 3 which does not contain a modified polyolefin showed excellent tensile properties, wear resistance and flame retardancy, although each characteristic was slightly inferior to Example 1 and the like. In addition, Example 5 using an organically treated clay mineral as a clay mineral shows excellent tensile properties, wear resistance and flame retardancy, although the abrasion resistance is slightly inferior to Example 1 and the like. It was.

On the other hand, Comparative Example 1 containing no clay mineral had a problem in wear resistance, and Comparative Example 2 in which the content of magnesium hydroxide exceeded 150 parts by weight had a problem in tensile properties (tensile elongation). Moreover, the comparative example 3 which a resin mixture consists only of polypropylene has a problem in a tensile characteristic (tensile elongation),
In addition, the wear resistance was poor. Comparative Example 4 having a polypropylene content of less than 40% by mass has an abrasion resistance, and Comparative Example 5 having no modified styrene thermoplastic elastomer has an ethylene copolymer for tensile properties (tensile elongation) and abrasion resistance. Comparative Example 6 not containing each had a problem in wear resistance.

The flame retardant resin composition of the present invention is a flame retardant resin composition that is excellent in wear resistance and balanced in various properties such as flame retardancy and mechanical properties. -It can be advantageously used as an insulating coating material for electric wires arranged in electronic equipment, as a constituent member of the automobile or the like.

Claims (4)

(A) Polypropylene resin 40 to 90 mass%, (b) Ethylene copolymer 5 to 20 mass%, (c) Modified styrene thermoplastic elastomer 5 to 20 mass%, and (d) Modified polyolefin 0 to 20 For 100 parts by mass of the resin mixture consisting of mass%,
(E) Magnesium hydroxide 40 to 150 parts by mass, and (f) a clay mineral 1 to 20 parts by mass, a flame retardant resin composition. The flame retardant resin composition according to claim 1, wherein the (e) magnesium hydroxide is not subjected to a surface treatment. The mass ratio of the (b) ethylene copolymer to the (c) modified styrene thermoplastic elastomer is ethylene copolymer / modified styrene thermoplastic elastomer = 2/1 to 1/1 /.
The flame retardant resin composition according to claim 1, wherein the flame retardant resin composition is 2. An insulated wire obtained by extrusion-coating a flame retardant resin composition according to any one of claims 1 to 3 on a conductor.