JP2010095638A - Non-halogen flame retardant resin composition and non-halogen flame retardant electric wire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a non-halogen flame retardant resin having high flame retarding property and insulation property, without the reduction of mechanical properties such as elongation, tensile strength, etc., and a non-halogen flame retardant electric wire by using the same. <P>SOLUTION: This non-halogen flame retardant resin composition is provided by adding the non-halogen flame retardant to 100 pts.wt. base polymer containing 60 to 80 pts.wt. ethylene-vinyl acetate copolymer (EVA) containing ≥40 wt.% vinyl acetate content and having 0.1 to 1.0 g/10 min melt flow rate (MFR) measured at a load of 2.16 kg and at 190°C, and 40 to 20 pts.wt. ethylene-ethyl acrylate copolymer (EEA) containing 10 to 20 wt.% ethyl acrylate content and having 0.5 g/10 min MFR, and having ≤0.5 MFR ratio of the EVA to the EEA, followed by cross-linking. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a halogen-free flame retardant resin composition and a halogen-free flame retardant electric wire, and particularly to a halogen-free flame retardant electric wire in which an insulator and / or a sheath made of a halogen-free flame retardant resin composition is coated on a conductor. It is.

Conventionally, a non-halogen flame retardant electric wire uses a flame retardant resin composition that does not contain a halogen compound as an insulator. As the flame retardant resin composition not containing a halogen compound, a composition obtained by adding a metal hydroxide such as magnesium hydroxide to a polyolefin resin is used.
These compositions are characterized in that no toxic gases such as hydrogen chloride and dioxin are generated during combustion. Therefore, generation of toxic gas at the time of fire, secondary disasters, etc. can be prevented, and incineration at the time of disposal does not pose a problem.

  However, there are many cases where the desired flame retardancy cannot be obtained simply by adding the metal hydroxide alone. Therefore, it has been conventionally performed to add a phosphorus-containing flame retardant such as red phosphorus as a flame retardant aid for improving the flame retardancy.

  However, when a resin composition to which a phosphorus-containing flame retardant such as red phosphorus is added is used for the wire coating, there is a problem that the surface of the wire cannot be colored in an arbitrary color due to the color development of red phosphorus. In addition, the phosphorus-containing flame retardant also has a problem of generating phosphine gas in a high temperature and high humidity environment, for example, when used or discarded.

  Instead of adding a phosphorus-containing flame retardant such as red phosphorus, increasing the amount of metal hydroxide added to improve flame retardancy, along with this, mechanical properties such as elongation and tensile strength of the resin composition However, there is a problem that the remarkably decreases.

  In addition, as a related technique, in order to suppress the heat aging property of the resin composition which becomes a problem by increasing the amount of addition of the metal hydroxide, the base resin of the resin composition is composed of an ethylene / vinyl acetate copolymer. (For example, refer to Patent Document 1). Similarly, as a related technique, there is a technique of adding a 1,3,5 triazine derivative and a specific metal to the resin composition in order to improve flame retardancy without using a phosphorus-containing flame retardant such as red phosphorus. (For example, refer to Patent Document 2).

JP 2002-42574 A JP 2003-113276 A

  However, in order to improve flame retardancy, a resin composition in which the proportion of vinyl acetate in the ethylene-vinyl acetate copolymer is increased in the base polymer has a low volume resistivity and is required as a wire coating. Insulation may be insufficient.

  That is, even if the thermal aging property of the resin composition is suppressed as in the past (Patent Document 1) or the flame retardancy is improved as in the past (Patent Document 2), the resin composition is used as a wire coating. When used, the volume resistivity may be low, and there may be a problem that the insulating property is insufficient.

  An object of the present invention is to provide a non-halogen flame-retardant resin composition having high flame retardancy and insulation while suppressing deterioration of mechanical properties such as elongation and tensile strength, and a non-halogen flame-retardant electric wire using the same. There is.

  In the first aspect of the present invention, the vinyl acetate content is 40 wt% or more, and the melt flow rate (MFR) measured at 190 ° C. and 2.16 kg applied load is 0.1 to 1.0 g / 10 min. An ethylene-ethyl acrylate copolymer (EEA) having an ethylene-vinyl acetate copolymer (EVA) of 60-80 parts by weight, an ethyl acrylate content of 10-20 wt%, and an MFR of 0.5 g / 10 min or more. A non-halogen flame retardant is added to 100 parts by weight of a base polymer containing 40 to 20 parts by weight, and the MFR ratio between the EVA and the EEA is 0.5 or less, and is crosslinked.

  In the second aspect of the present invention, the vinyl acetate content is 40 wt% or more, and the melt flow rate (MFR) measured at 190 ° C. and 2.16 kg applied load is 0.1 to 1.0 g / 10 min. An ethylene-ethyl acrylate copolymer (EEA) having an ethylene-vinyl acetate copolymer (EVA) of 60-80 parts by weight, an ethyl acrylate content of 10-20 wt%, and an MFR of 0.5 g / 10 min or more. The non-halogen flame retardant is added and crosslinked with respect to 100 parts by weight of a base polymer comprising 40 to 20 parts by weight, the EVA being a dispersed phase and the EEA forming a continuous phase. .

  According to a third aspect of the present invention, in the invention described in the first or second aspect, the non-halogen flame retardant comprises a metal hydroxide and a 1,3,5 triazine derivative, and the base polymer is added in an amount of 100 parts by weight. On the other hand, 50 to 250 parts by weight of the metal hydroxide and 5 to 20 parts by weight of the 1,3,5 triazine derivative are added.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, 0.5 to 5 parts by weight of an organic peroxide is added to 100 parts by weight of the base polymer. It is characterized by.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the ethylene copolymer 1 to 100 parts by weight of the base polymer modified with maleic acid or a derivative thereof are used. 10 parts by weight are added to the base polymer.

According to a sixth aspect of the present invention, in the invention according to any one of the first to fifth aspects, the volume resistivity is 10 ¹³ Ω · cm or more.

  A seventh aspect of the present invention is a halogen-free flame retardant electric wire using the halogen-free flame retardant resin composition according to any one of the first to sixth aspects.

  According to the present invention, a non-halogen flame retardant resin composition having high flame retardancy and insulation properties and a non-halogen flame retardant electric wire using the same can be obtained while suppressing deterioration of mechanical properties such as elongation and tensile strength. .

The inventors have made various studies on non-halogen flame retardant resin compositions having high flame retardancy and insulation without significantly impairing mechanical properties such as elongation and tensile strength.
As a result, the ethylene-vinyl acetate copolymer and the ethylene-ethyl acrylate copolymer were kneaded to form a base polymer, and the melting flow rate of the ethylene-ethyl acrylate copolymer was changed to that of the ethylene-vinyl acetate copolymer. The knowledge that it is higher than the ting flow rate was obtained.
That is, as shown in FIG. 1, in the base polymer, an ethylene-vinyl acetate copolymer (EVA) responsible for flame retardancy becomes a dispersed phase (island phase), and an ethylene-ethyl acrylate copolymer responsible for insulation. It has been found that by making a phase structure (sea-island structure) in which (EEA) is a continuous phase (sea phase), it is possible to achieve both flame retardancy and insulation while suppressing deterioration of mechanical properties. .
Based on this knowledge, the best mode for carrying out the present invention will be described.

FIG. 2A shows a cross-sectional structure of an embodiment of a non-halogen flame retardant electric wire to which the present invention is applied.
As shown in FIG. 2 (a), the above-mentioned electric wire is obtained by covering the outer periphery of a long metal conductor 1 with a round cross section with an insulator 2 made of a non-halogen flame retardant resin composition. is there. Examples of the metal conductor 1 include a copper alloy. As the metal conductor 1, for example, a copper wire may be used as a single wire, or may be used as a plurality of stranded wires or knitted wires, and the copper wire may be subjected to hot dipping or tin plating by electrolysis.
The cross-sectional shape of the electric wire is not limited to a round shape. In other words, the electric wire may be a flat metal conductor obtained by slitting based on a plate-like copper plate or rolling a round wire, and covering the insulator.

FIG. 2B shows a cross-sectional structure of another embodiment of a non-halogen flame retardant electric wire to which the present invention is applied.
As shown in FIG. 2 (b), in the electric wire, the outer periphery of the conductor 1 is covered with the insulator 2 made of the non-halogen flame retardant resin composition in the present embodiment, and the outer periphery is further coated with the non-halogen flame retardant resin composition. The sheath 3 is made of a material.

Hereinafter, the non-halogen flame retardant resin composition constituting the insulator 2 and / or the sheath 3 will be described in detail.
The non-halogen flame retardant resin composition is non-halogen resistant to a base polymer containing an ethylene-vinyl acetate copolymer (hereinafter also referred to as EVA) and an ethylene-ethyl acrylate copolymer (hereinafter also referred to as EEA). A flame retardant is added and crosslinked.

  The ethylene-vinyl acetate copolymer (EVA) has a vinyl acetate content (hereinafter referred to as VA amount, also referred to as VA) of 40 wt% or more, a melt flow rate (measured at 190 ° C. and 2.16 kg). MFR) of 0.1 to 1.0 g / 10 min is used.

Here, EVA is used to improve flame retardancy.
The reason why the VA amount of EVA is limited to 40 wt% or more is that a sufficient flame retardant effect cannot be obtained when the content is less than 40 wt%.
Further, the reason why the MFR is set to 0.1 to 1.0 g / 10 min is that when it is larger than 1.0 g / 10 min, characteristics such as tensile strength are significantly deteriorated.

  The ethylene-ethyl acrylate copolymer (EEA) has an ethyl acrylate content (hereinafter also referred to as EA amount, also referred to as EA) of 10 to 20 wt% and an MFR of 0.5 g / 10 min or more. Kneaded with EVA.

Here, EEA is used in order to improve insulation while suppressing a decrease in flame retardancy.
The reason why the EA amount of EEA is limited to 10 to 20 wt% is that when the content is less than 10 wt%, the compatibility with EVA is lowered, the dispersion becomes poor, and sufficient mechanical properties cannot be obtained.
This is because if it exceeds 20 wt%, a sufficient insulating effect cannot be obtained.
The reason why the MFR is set to 0.5 g / 10 min or more is that sufficient insulation characteristics cannot be obtained with an EEA having an MFR of less than 0.5.

  The EVA content in 100 parts by weight of the base polymer is preferably 60 to 80 parts by weight, and the EEA content is preferably 40 to 20 parts by weight. This is because sufficient flame retardancy and insulating properties cannot be obtained unless the contents of EVA and EEA are within the above ranges.

Here, in the present embodiment, the ratio of EVA and MEA MFR is set as follows.
That is, the value of (EVA MFR) / (EEA MFR) is set to 0.5 or less.

  By setting the ratio of MFR of EVA and EEA within the above range, the resin composition can achieve both flame retardancy and insulation without significantly impairing mechanical properties.

  Specifically, according to the present embodiment, as shown in FIG. 1, the structure of the resin composition obtained by kneading EVA and EEA includes EVA as a dispersed phase (island phase) and EEA as a continuous phase (sea phase). Phase structure (sea-island structure). By achieving the phase structure as described above, the dispersibility of EVA which is a dispersed phase and bears flame retardancy is improved. By improving the dispersibility of EVA, flame retardancy can be improved while suppressing a decrease in mechanical properties. Furthermore, EEA which is a continuous phase and bears insulation can sufficiently exhibit insulation.

The EVA and the EEA may be mixed with other ethylene copolymers or polyolefin resins.
Specific examples of the ethylene copolymer and polyolefin resin include the following. Low density, medium density, and high density polyethylene, linear low density polyethylene, linear ultra-low density polyethylene, ethylene-methacrylate copolymer, ethylene-styrene copolymer, ethylene-propylene copolymer, ethylene-butene A copolymer, an ethylene-octene copolymer, and a graft polymer of these and maleic anhydride may be used alone or in combination.

The ethylene copolymer is particularly preferably an ethylene copolymer modified with maleic acid or a derivative thereof. This is because the portion modified with maleic acid increases the adhesion with the metal hydroxide, thereby improving dispersibility and mechanical properties.
Specific examples of the ethylene copolymer modified with maleic acid or a derivative thereof include maleic acid-modified EEA, maleic acid-modified EVA, maleic acid-modified SEBS, and the like.
The addition amount of the ethylene copolymer modified with maleic acid or a derivative thereof is preferably 1 to 10 parts by weight in 100 parts by weight of the base polymer. If the amount is less than 1 part by weight, the tensile strength property is not improved, and if it is used more than 10 parts by weight, the elongation property of the entire resin composition is lowered.

  Next, the non-halogen flame retardant added to the base polymer will be described.

  As the non-halogen flame retardant added to the base polymer, metal hydroxides and 1,3,5-triazine derivatives are preferable.

Specific examples of the metal hydroxide include calcium hydroxide and these metal hydroxides in which nickel is dissolved. These may be used alone or in combination of two or more. These metal hydroxides may be silane coupling agents, titanate coupling agents, fatty acids such as stearates and calcium stearates, or those surface-treated with fatty acid metal salts. Further, an appropriate amount of other metal hydroxide may be added.

  In this embodiment, the amount of the metal hydroxide added is preferably 50 to 250 parts by weight with respect to 100 parts by weight of the base polymer. This is because if the amount added is less than 50 parts by weight, sufficient flame retardancy cannot be obtained, and if it is more than 250 parts by weight, the mechanical properties remarkably deteriorate.

  On the other hand, specific examples of the 1,3,5-triazine derivative added to the base polymer include melamine, cyanuric acid, isocyanuric acid, melamine cyanurate, and melamine sulfate. More preferred is melamine cyanurate. These may be surface-treated with a nonionic surfactant or various coupling agents.

  In the present embodiment, the amount of the 1,3,5-triazine derivative added is preferably 5 to 20 parts by weight with respect to 100 parts by weight of the base polymer. This is because if the amount added is less than 5 parts by weight, a sufficient flame retarding effect cannot be obtained, and if it is more than 20 parts by weight, the mechanical strength is significantly reduced.

  Next, a cross-linking method and a cross-linking agent used when cross-linking the resin composition obtained by adding the non-halogen flame retardant to the base polymer will be described.

As the crosslinking method, peroxide crosslinking is preferable. This is because peroxide crosslinking has a higher degree of crosslinking and improved tensile strength compared to silane crosslinking and irradiation crosslinking.
Moreover, as said crosslinking agent, an organic peroxide is preferable. Specifically, dicumyl peroxide, 1,3-bis (t-butylperoxyisopropyl) benzene, 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane, 1,1 -Bis (t-butylperoxy) 3,3,5-trimethylcyclohexane, benzoyl peroxide, benzoyl m-methylbenzoyl peroxide, m-toluoyl peroxide, t-hexyl p-oxybenzoate, 1,1-bis (T-butylperoxy) 2-methylcyclohexane, 1,1-bis (t-hexylperoxy) cyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, 2,2-bis (4,4- Dibutylperoxycyclohexyl) propane, 1,1-bis (t-butylperoxy) cyclododeca , T-hexylperoxyisopropyl monocarbonate, succinic acid peroxide, 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanate, t-hexylperoxy-2-ethylhexanate, t-butylperoxy-2-ethyl Hexanate, 2,5-dimethyl-2,5-di (m-toluoylperoxy) hexane, t-butylperoxyisopropyl monocarbonate, t-butylperoxy 2-ethylhexyl monocarbonate, 2,5- Examples include dimethyl-2,5-di (benzoylperoxy) hexane, t-butylperoxyacetate, 2,2-bis (t-butylperoxy) butane, and more preferably 1,3-bis ( t-butylperoxyisopropyl) benzene.

  In this embodiment, the amount of the organic peroxide added is preferably 0.5 to 5 parts by weight, more preferably 1 to 3 parts by weight with respect to 100 parts by weight of the base polymer. If the blending amount is less than 0.5 parts by weight, the crosslinking cannot be sufficiently achieved, and if it exceeds 5 parts by weight, the crosslinking proceeds so much that the elongation decreases.

In addition, in the resin composition of this embodiment, in addition to the said organic peroxide which is a crosslinking agent, a crosslinking adjuvant can be used as needed. Thereby, uniform and efficient crosslinking reaction can be performed.
Examples of the crosslinking aid include, for example, triallyl cyanurate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, and polyethylene glycol dimethacrylate having 9 to 14 repeating units of ethylene glycol. , Trimethylolpropane trimethacrylate, allyl methacrylate, polyfunctional methacrylate compounds such as 2-methyl-1,8-octanediol dimethacrylate, 1,9-nonanediol dimethacrylate, polyethylene glycol diacrylate, 1,6-hexane Multifunctional acrylates such as diol diacrylate, neopentyl glycol diacrylate, propylene glycol diacrylate Compounds, and vinyl butyrate or vinyl stearate and the like.

  In addition to the above additives, additives such as antioxidants, lubricants, softeners, plasticizers, inorganic fillers, compatibilizers, stabilizers, carbon black, and colorants can be added as necessary. is there.

The non-halogen flame retardant electric wire of the above embodiment is manufactured by, for example, using an ordinary extrusion molding line, melt-kneading the resin composition, and extruding the non-halogen flame retardant resin composition onto one or more metal conductors. it can. For melt kneading, for example, a batch kneader or a twin screw extruder is used. Moreover, for example, a twin screw extruder is used for the extrusion line. With this twin-screw extruder, the melt-kneaded resin composition is extruded, and the metal conductor is coated with this resin composition to form a coating layer.
The halogen-free flame retardant resin composition thus produced preferably has a volume resistivity of 10 ¹³ Ω · cm or more. This is because sufficient insulation is required when a non-halogen flame retardant electric wire is put into practical use.

As a result, by using the non-halogen flame retardant resin composition as an insulator or sheath, no harmful gas is generated during use, and mechanical strength is not significantly impaired, and high flame retardancy and high insulation properties are obtained. A non-halogen flame retardant electric wire can be obtained.
The electric wire is suitable for, for example, in-device wiring, automobiles, robots, and vehicles.

  In Examples 1-12 and Comparative Examples 1-13, the non-halogen flame retardant electric wire having the structure shown in FIG. The said electric wire and the non-halogen flame-retardant resin composition used for the said electric wire were produced as follows.

  The various components used as the raw material of a resin composition were mix | blended with the compounding ratio shown in Examples 1-12 of Table 1, and Comparative Examples 1-13 of Table 2. The above blend was kneaded with a 25 L pressure kneader at a start temperature of 40 ° C. and an end temperature of 190 ° C., and then the kneaded product was pelletized. The pellet was continuously vulcanized and extruded at a thickness of 1.0 mm through a separator on the metal conductor 1 to form an insulator 2 covered with the metal conductor 1. Immediately after the extrusion, the insulator 2 covered with the metal conductor 1 was exposed to steam at 190 ° C. for 3 minutes. Thus, the electric wire used as the sample used in Examples 1-12 and Comparative Examples 1-13 was obtained.

<Examples 1 to 12>
Here, Examples 1 to 12 described in Table 1 will be described in detail.

In Examples 1 to 4, the ethylene-vinyl acetate copolymer (EVA) has a melt flow measured with a vinyl acetate content (VA) of 40 wt% or more, 190 ° C. and 2.16 kg applied load. The one having a rate (MFR) of 0.1 to 1.0 g / 10 min was used.
The ethylene-ethyl acrylate copolymer (EEA) has an ethyl acrylate content (
EA) is 10 to 20 wt%, and MFR is 0.5 g / 10 min or more.
Then, the EVA was blended while changing in the range of 60 to 80 parts by weight and the EEA in the range of 20 to 40 parts by weight to obtain 100 parts by weight of the base polymer.
To 100 parts by weight of the above base polymer, 150 parts by weight of magnesium hydroxide, which is a metal hydroxide as a non-halogen flame retardant, and 10 parts by weight of melamine cyanurate, which is a 1,3,5 triazine derivative, are added as a crosslinking agent. A resin composition to which 1.5 parts by weight of peroxide which is an organic peroxide was added was used.
In all the following examples including Examples 1 to 4, 1 part by weight of trimethylolpropane triacrylate as a crosslinking assistant and 100% by weight of a base polymer and an antioxidant (manufactured by AO-18 ADEKA) are used. 1 part by weight, 1 part by weight of an antioxidant (Irganox 1010 Ciba Geigy) was added, and 1 part by weight of zinc stearate was added as a lubricant.

  In Examples 5 to 12, 70 parts by weight of EVA having 42% by weight of VA and 0.2 g / 10 min of MFR and 30 parts by weight of EEA having 10% of EA and 0.5 g / 10 min of MFR were blended, The base polymer was 100 parts by weight.

  Here, in Examples 5 and 6, magnesium hydroxide was added in the range of 50 to 250 parts by weight, and 10 parts by weight of melamine cyanurate was added to 100 parts by weight of the base polymer. The resin composition which added 1.5 weight part of was used.

  In Examples 7 and 8, 150 parts by weight of magnesium hydroxide is added to 100 parts by weight of the base polymer, melamine cyanurate is added in the range of 5 to 20 parts by weight, and peroxide is added. A resin composition added with 1.5 parts by weight was used.

  In Examples 9 and 10, 150 parts by weight of magnesium hydroxide was added to the polymer in which maleic acid-modified EEA was added to the base polymer in the range of 1 to 10 parts by weight with respect to 100 parts by weight of the base polymer. Then, a resin composition to which 10 parts by weight of melamine cyanurate was added and 1.5 parts by weight of peroxide was added was used.

  In Examples 11 and 12, magnesium hydroxide was added to a polymer obtained by adding 10 parts by weight of maleic acid-modified EEA to the base polymer as an ethylene copolymer modified with maleic acid with respect to 100 parts by weight of the base polymer. Was added in an amount of 150 parts by weight, 10 parts by weight of melamine cyanurate was added, and a peroxide was added in the range of 0.5 to 5 parts by weight.

<Comparative Examples 1-13>
About Comparative Examples 1-13, the resin composition which added the flame retardant, crosslinking agent, crosslinking adjuvant, antioxidant, and lubricant of the quantity of Table 2 to the polymer mix | blended as Table 2 was used.

Evaluation of the electric wire in Examples 1-12 and Comparative Examples 1-13 was determined by the method shown below.
(1) Tensile test The electric wire produced as described above was subjected to a tensile test according to EN60811. The tensile strength of less than 10 MPa was rejected (x), and the tensile strength was determined to be acceptable (◯). For the elongation, less than 150% was rejected (x), and more than that was passed (◯).
(2) Flame retardance test The produced electric wire was subjected to a vertical combustion test according to UIC standard CODE 895 OR 3rd edition 5.3.43. In the judgment, those with a combustion time of 30 seconds or more after removing the flame were regarded as unacceptable (x), and those less than that were regarded as acceptable (◯).
(3) Insulation test The pellets produced as described above were kneaded with a roll, press-molded at 120 ° C., then pressurized and crosslinked at 190 ° C. for 3 minutes to produce a 1 mm thick sheet, and the volume at room temperature DC 500 V The resistivity was measured with a volume resistance meter. A volume resistivity of 1.0 × 10 ¹³ Ω · cm or more was accepted.
The result obtained by the said test was described in Table 1 about Examples 1-12, and Table 2 about Comparative Examples 1-13. Table 1 and Table 2 also show the MFR ratio between EVA and EEA, that is, the value of (EVA MFR) / (EEA MFR).

  In Examples 1 to 12 shown in Table 1, the tensile strength / elongation and the vertical combustion test all passed, the volume resistivity satisfied the target, and good characteristics were exhibited.

  On the other hand, in Comparative Examples 1 to 13 shown in Table 2, the evaluation was poor in one or more of the tests (1) to (3).

In Comparative Example 1, the EVA VA was 33 wt%, which was less than the range of 40 wt% or more, and the flame retardancy was insufficient.
In Comparative Example 2, the MFR of EVA was 1.2 g / 10 min, which was higher than the range of 0.1 to 1.0 g / 10 min, and the tensile properties and the insulating properties were insufficient.

In Comparative Example 3, in 100 parts by weight of the base polymer, EVA is 90 parts by weight, more than the range of 60-80 parts by weight, and EEA is 10 parts by weight, more than the range of 40-20 parts by weight. The insulation was insufficient.
In Comparative Example 4, in 100 parts by weight of the base polymer, EVA is 50 parts by weight, less than the range of 60-80 parts by weight, and EEA is 50 parts by weight, more than the range of 40-20 parts by weight. Many flame retardants were insufficient.

In Comparative Example 5, the EA of EEA was 8 wt%, less than the range of 10 to 20 wt%, and the tensile properties were insufficient.
In Comparative Example 6, the MFR of EEA was 0.4 g / 10 min, smaller than the range of 0.5 g / 10 min or more, and the insulation was insufficient.

  In Comparative Example 7, the MFR ratio of EVA to EEA, that is, the value of (EVA MFR) / (EEA MFR) was 0.625, which was larger than the range of 0.5 or less, and the insulation was insufficient. It was.

In Comparative Example 8, magnesium hydroxide as a flame retardant was 45 parts by weight, less than the range of 50 to 250 parts by weight, and the flame retardancy was insufficient.
On the contrary, in Comparative Example 9, magnesium hydroxide as a flame retardant was 275 parts by weight, more than the range of 50 to 250 parts by weight, and the tensile properties were insufficient.

In Comparative Example 10, melamine cyanurate, which is a 1,3,5 triazine derivative as a flame retardant, was 4 parts by weight, less than the range of 5 to 20 parts by weight, and the flame retardancy was insufficient.
Conversely, in Comparative Example 11, melamine cyanurate, which is a 1,3,5 triazine derivative as a flame retardant, was 21 parts by weight, more than the range of 5 to 20 parts by weight, and the tensile properties were insufficient. .

In Comparative Example 12, the peroxide as a crosslinking agent was 0.4 parts by weight, less than the range of 0.5 to 5 parts by weight, and the tensile strength was insufficient among the tensile properties.
On the contrary, in Comparative Example 13, the peroxide as the crosslinking agent was 6 parts by weight, more than the range of 0.5 to 5 parts by weight, and the elongation was insufficient among the tensile properties.

It is explanatory drawing which shows a mode that the phase structure (sea island structure) in which EVA becomes a disperse phase (island phase) and the said EEA becomes a continuous phase (sea phase) in the base polymer in this embodiment. (A) It is a figure which shows the cross-section of one Embodiment of the electric wire which coat | covered the metal conductor with the insulator in this embodiment. (B) It is a figure which shows the cross-section of one Embodiment of the electric wire which coat | covered the metal conductor with the insulator in this embodiment, and coat | covered with the sheath on it.

Explanation of symbols

1 Metal conductor 2 Insulator 3 Sheath

Claims (7)

An ethylene-vinyl acetate copolymer (EVA) having a vinyl acetate content of 40 wt% or more and a melt flow rate (MFR) of 0.1 to 1.0 g / 10 min measured at 190 ° C. and an applied load of 2.16 kg. ) 60 to 80 parts by weight,
Including 40 to 20 parts by weight of an ethylene-ethyl acrylate copolymer (EEA) having an ethyl acrylate content of 10 to 20 wt% and an MFR of 0.5 g / 10 min or more,
A non-halogen flame retardant resin composition obtained by adding a non-halogen flame retardant to 100 parts by weight of a base polymer having an MFR ratio of EVA and EEA of 0.5 or less, and crosslinking. An ethylene-vinyl acetate copolymer (EVA) having a vinyl acetate content of 40 wt% or more and a melt flow rate (MFR) of 0.1 to 1.0 g / 10 min measured at 190 ° C. and a load of 2.16 kg. ) 60 to 80 parts by weight,
40 to 20 parts by weight of an ethylene-ethyl acrylate copolymer (EEA) having an ethyl acrylate content of 10 to 20 wt% and an MFR of 0.5 g / 10 min or more,
A non-halogen flame retardant resin composition comprising a non-halogen flame retardant added to 100 parts by weight of a base polymer in which the EVA forms a dispersed phase and the EEA forms a continuous phase. The non-halogen flame retardant comprises a metal hydroxide and a 1,3,5 triazine derivative;
For 100 parts by weight of the base polymer,
The halogen-free flame retardant resin composition according to claim 1 or 2, wherein 50 to 250 parts by weight of the metal hydroxide and 5 to 20 parts by weight of the 1,3,5 triazine derivative are added. For 100 parts by weight of the base polymer,
The halogen-free flame retardant resin composition according to any one of claims 1 to 3, wherein 0.5 to 5 parts by weight of an organic peroxide is added. For 100 parts by weight of the base polymer,
The halogen-free flame retardant resin composition according to any one of claims 1 to 5, wherein 1 to 10 parts by weight of an ethylene copolymer modified with maleic acid or a derivative thereof is added to the base polymer. The non-halogen flame retardant resin composition according to claim 1, wherein the volume resistivity is 10 ¹³ Ω · cm or more.   A non-halogen flame-retardant electric wire using the non-halogen flame-retardant resin composition according to claim 1.

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