JP2007246726A - Flame-retardant resin composition, manufacturing method of the 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 that is excellent in abrasion resistance, and has well balanced properties with respect to flame retardancy mechanical properties, and the like, and to provide a manufacturing method of the resin composition and an insulated wire coated with the resin composition. <P>SOLUTION: The flame-retardant resin composition comprises 40-150 pts.mass of magnesium hydroxide being not surface-treated, based on 100 pts.mass of a resin mixture comprising 40-90 mass% of a polypropylene-based resin, 5-20 mass% of an ethylenic copolymer, 5-20 mass% of a modified styrenic thermoplastic elastomer, and 0-20 mass% of a modified polyolefin, and is best-suited for an insulating material for an electric wire to be installed in automobiles or an electric/electronic device and for a member, etc. of the automobile, etc. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a flame retardant resin composition, a method for producing the 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, etc., a method for producing the resin composition, 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 flame retardants containing bromine (Br) atoms or chlorine (Cl) atoms in the molecule are widely used as the resin material 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. are eluted as phosphorus compounds, plasticizers and heavy metal stabilizers, and corrosive halogen gases and dioxins are 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 those of 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-mentioned problems, and has excellent wear resistance, and furthermore, a flame retardant resin composition balanced in flame retardancy and mechanical properties, and a method for producing the resin composition And it is providing the insulated wire which coat | covered the said resin composition.

  In order to solve the above-mentioned 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) modification. (E) Magnesium hydroxide 40 to 150 mass not subjected to surface treatment with respect to 100 mass parts of a resin mixture composed of 5 to 20 mass% of a styrenic thermoplastic elastomer and (d) 0 to 20 mass% of a modified polyolefin. Part is contained.

  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 method for producing a flame retardant resin composition of the present invention is a method for producing the flame retardant resin composition of the present invention as described above, wherein the polypropylene resin and magnesium hydroxide not subjected to surface treatment are melted. The method includes a step of kneading into a melt-kneaded product, and a step of further melt-kneading the ethylene-based copolymer, the modified styrenic thermoplastic elastomer and the modified polyolefin into the melt-kneaded product.

  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, and surface-treats a resin mixture comprising other specific amounts of an ethylene copolymer, a modified styrene thermoplastic elastomer and a modified polyolefin. Adopted a composition containing a specific amount of magnesium hydroxide that has not been subjected to heat treatment, it has excellent wear resistance in addition to heat resistance and cold resistance, and also has good flame resistance and mechanical properties. It becomes a flame-retardant resin composition having various properties in a well-balanced manner.

  Further, the flame retardant resin composition of the present invention has an ethylene copolymer / modified styrene thermoplastic elastomer mass ratio of ethylene copolymer / modified styrene thermoplastic elastomer = 2/1 to 1/1 /. Since it is 2, the abrasion resistance of the resin composition can be further improved.

  The production method of the flame retardant resin composition of the present invention is such that, in producing the flame retardant resin composition of the present invention described above, first, a polypropylene resin and magnesium hydroxide not subjected to surface treatment are melt-kneaded. In this way, an ethylene copolymer, a modified styrene thermoplastic elastomer and a modified polyolefin are further melt-kneaded in this melt-kneaded product. Dispersibility is improved, and wear resistance and mechanical properties are 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”) includes (a) 40 to 90% by mass of a polypropylene resin and (b) 5 to 20 mass of an ethylene copolymer. %, (C) 5 to 20% by mass of a modified styrene-based thermoplastic elastomer, and (d) 100 parts by mass of a resin mixture consisting of 0 to 20% by mass of a modified polyolefin. It contains 40 to 150 parts by mass of magnesium oxide.

(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 and those obtained by copolymerizing propylene with an α-olefin such as ethylene and 1-butene. Specific examples include homopolypropylene, block polypropylene, random polypropylene, propylene-ethylene random copolymer, and propylene-butene random copolymer.

  Moreover, as such a polypropylene resin, the hardness (HRR) is 65 or more, considering that the resin composition of the present invention is used as an insulating coating material for members and insulated wires that require wear resistance, It is preferable to use polypropylene having 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 10.0 g / 10 min or less (230 ° C., 2 ° C.) from the viewpoint of improving the kneadability of the resin composition. .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. Examples of the ethylene copolymer that can be used in the present invention include an ethylene / vinyl acetate copolymer, an ethylene / acrylic acid copolymer, an ionomer, an ethylene / methyl acrylate copolymer, an ethylene / ethyl acrylate copolymer, And ethylene / butyl acrylate copolymer.

  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 copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), and 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 preferably 10.0 g / 10 min or less (230 ° C., 2.16 kgf 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 mixture of magnesium hydroxide not subjected to surface treatment (e), which is a non-resin component described later, and further has mechanical properties. It has a function to improve 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. Magnesium hydroxide includes 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 in the present invention, water that has not been surface-treated. By employing magnesium oxide, the wear resistance of the resin composition can be further improved. Examples of magnesium hydroxide that has not been surface-treated include “Magnifine H7” (manufactured by Albemarle), Kisuma 5 (manufactured by Kyowa Chemical Industry Co., Ltd.), and the like.

  In order to make the dispersibility with respect to the resin mixture good, the magnesium hydroxide preferably has, for example, an average particle diameter in the range of 0.3 to 1.5 μm and almost no aggregation. The average particle size is particularly preferably about 0.5 to 1.0 μm.

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, (a) polypropylene resin, (b) ethylene copolymer, (c) modified styrene thermoplastic elastomer, (d) It is 40-90 mass% with respect to the whole resin mixture which consists of modified polyolefin. 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. . If the content of the ethylene copolymer or modified styrene thermoplastic elastomer is less than 5% by mass, the mechanical properties and cold resistance may be lowered. On the other hand, if the content exceeds 20% by mass, the wear resistance is reduced. And heat resistance may be reduced. 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. If the total content is less than 10% by mass, the mechanical properties and cold resistance of the resin composition may be reduced. On the other hand, if it exceeds 40% by mass, the heat resistance and wear resistance of the resin composition may be reduced. May decrease. The total content of the ethylene copolymer and the modified styrene thermoplastic elastomer is particularly preferably 10 to 20% by mass.

  The content of the (d) modified polyolefin in the resin composition is 0 to 20% by mass of the entire resin mixture. When the content of the modified polyolefin exceeds 20% by mass, the fluidity of the resin composition is lowered, and there may be a problem 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. By containing the modified polyolefin, the dispersibility of 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 not subjected to surface treatment in the resin composition is 40 to 150 parts by mass with respect to 100 parts by mass of the resin mixture. If the magnesium hydroxide content 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 obtained. Adversely affects sex and increases specific gravity. The content of magnesium hydroxide not subjected to surface treatment is preferably 60 to 120 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, cross-linking agents, cross-linking aids, etc., and depending on the application, conventionally used red phosphorus, polyphosphate compounds, zinc hydroxystannate, zinc stannate, zinc borate, calcium carbonate, hydrotalcite A flame retardant aid such as 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 the flame-retardant resin composition, a step of melt-kneading a polypropylene resin and magnesium hydroxide (and additives if necessary) not subjected to surface treatment to obtain a melt-kneaded product in advance The melt-kneaded product may be manufactured so as to include a step of further melt-kneading the remaining materials (ethylene copolymer, modified styrene thermoplastic elastomer, modified polyolefin). By doing in this way, there exists an effect that the dispersibility of the magnesium hydroxide in a resin composition improves, and abrasion resistance and a mechanical characteristic further improve. The kneading temperature is preferably set to be equal to or lower than the decomposition temperature of magnesium hydroxide (for example, 340 ° C. or lower). In addition, about other manufacturing conditions, such as extrusion amount, it can determine suitably with kinds, such as a resin component to be used.

  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, and surface-treats a resin mixture comprising other specific amounts of an ethylene copolymer, a modified styrene thermoplastic elastomer and a modified polyolefin. Adopted a composition containing a specific amount of magnesium hydroxide that has not been subjected to heat treatment, it has excellent wear resistance in addition to heat resistance and cold resistance, and also has good flame resistance and mechanical properties. It becomes a flame-retardant resin composition having various properties in a well-balanced manner. And it is easy to recycle even after disposal, and even if it is disposed of such as buried, it does not cause problems of environmental pollution 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 restriction | limiting in particular in the shape of this resin molding, For example, a power plug, a connector, a sleeve, a box, a tape base material, a tube, a sheet | seat 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 and 2 and Comparative Examples 1 to 4]
Table 1 shows the configurations (materials used and contents) of the flame-retardant resin compositions of Examples 1 and 2 and Comparative Examples 1 to 4. The flame-retardant resin composition was manufactured by using a Banbury mixer as a kneading machine, melt-kneading a polypropylene resin, magnesium hydroxide, an antioxidant, and a lubricant to obtain a melt-kneaded product, and then adding the remaining material to the melt-kneaded product. The materials (ethylene copolymer, modified styrene thermoplastic elastomer, modified polyolefin) were further melt-kneaded and pelletized.

  The details of the materials used are as follows. The melt flow rate (MFR) was measured under the following temperature and load conditions in accordance with JIS K7210. Here, the content in Table 1 is shown as parts by mass when the total resin mixture is 100 parts by mass (for each of the resin materials constituting the resin mixture consisting of (1) to (4), the resin mixture It is the same as the content (mass%) when the whole 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: Magnificin H7 (Albemarle)
Surface treatment: None Average particle size: 1.0 μm

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

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

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

(Configuration of resin composition)

[Test Example 1]
The flame-retardant resin compositions of Example 1, Example 2, and Comparative Examples 1 to 4 were subjected to a general-purpose extrusion machine for electric wire production 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 wires were compared and evaluated for “tensile properties”, “flame resistance” and “abrasion resistance” according to the following criteria. The results are shown in Table 2.

(Tensile properties)
The tensile strength (MPa) and tensile elongation (%) of the insulation coating material of the obtained insulated wire were measured at a marked line of 50 mm and a tensile speed of 200 mm / min in accordance with JIS C3005. 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 of Table 2, the insulated wire obtained by extrusion coating the resin composition shown in the examples of the present invention showed excellent tensile properties, wear resistance and flame retardancy. In addition, Example 2 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.

  On the other hand, Comparative Example 1 using surface-treated magnesium hydroxide as magnesium hydroxide, Comparative Example 2 containing no modified styrene thermoplastic elastomer and modified polyolefin, ethylene copolymer (ethylene / acetic acid) Comparative Example 3 containing no vinyl copolymer) and modified polyolefin, Comparative Example 4 containing no ethylene copolymer and modified styrene thermoplastic elastomer had a problem in abrasion resistance, and Comparative Example 2 was a tensile property. (Tensile elongation) was also poor.

  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) A flame retardant resin composition containing 40 to 150 parts by mass of magnesium hydroxide that has not been surface-treated.   The mass ratio of the (b) ethylene copolymer and the (c) modified styrene thermoplastic elastomer is ethylene copolymer / modified styrene thermoplastic elastomer = 2/1 to 1/2. The flame-retardant resin composition according to claim 1. A method for producing the flame retardant resin composition according to claim 1 or 2,
A step of melt-kneading the polypropylene-based resin and magnesium hydroxide not subjected to surface treatment to obtain a melt-kneaded product;
A method for producing a flame-retardant resin composition, comprising the step of further melt-kneading an ethylene copolymer, a modified styrene thermoplastic elastomer and a modified polyolefin into the melt-kneaded product. An insulated wire obtained by extrusion-coating a flame retardant resin composition according to claim 1 or 2 on a conductor.