JP5776389B2 - Flame retardant composition having peelability and heat resistance, method for producing flame retardant resin, and insulated wire - Google Patents

Description

  The present invention relates to a flame retardant composition having peelability and heat resistance, a method for producing a flame retardant resin, and an insulated wire, and more specifically, used in places where high heat resistance is required, such as an engine room of an automobile. The present invention relates to a flame retardant composition suitable as a covering material for an insulated wire, a method for producing a flame retardant resin, and an insulated wire.

  Conventionally, high heat resistance is required for an insulated wire used in a high-temperature environment such as an automobile engine room. For this reason, crosslinked polyvinyl chloride (PVC) or crosslinked polyethylene that has been crosslinked by means such as electron beam irradiation has been used as a covering material for insulated wires used in such places.

  For example, Patent Document 1 discloses a silane-crosslinked polyolefin, a polyolefin, a metal hydrate, a phenol-based antioxidant, a sulfur-based antioxidant, a metal oxide having high heat resistance and flame retardancy, A flame retardant composition containing a copper damage inhibitor is disclosed.

JP 2010-174157 A

  However, the conventionally known flame retardant composition using silane-crosslinked polyethylene has high heat resistance that passes the ISO 6722 standard 150 ° C.-3000 hours long-term heat resistance evaluation test, but was used as a covering material for insulated wires. In some cases, the following problems were found.

  That is, when an insulated wire is used in a vehicle such as an automobile, generally, a plurality of insulated wires are bundled together to form a wire bundle, and a protective material is wound around the outer periphery of the wire bundle, so that the wire harness is often used.

  At this time, in the wire bundle, the wires come into contact with each other on the surface and are used for a long time in a high temperature environment such as an engine room. If the electric wires are bundled and left for a long time under such a high temperature environment, the electric wire surfaces adhere to each other. Although the detailed mechanism has not been elucidated as a cause, it is thought that uncrosslinked portions of the base resin polyethylene-based resin melt and adhere at high temperatures.

  The problem to be solved by the present invention is to solve the above-mentioned problems of the prior art, and a resin formed from a flame retardant composition having a silane-modified polyethylene resin as a base resin is, for example, As it is used as a covering material for insulated wires, the surfaces of the resin films can be easily separated after being left in contact with each other at a high temperature. It is in providing the flame-retardant composition which has, the manufacturing method of a flame-retardant resin, and an insulated wire.

In order to solve the above problems, the flame retardant composition according to the present invention is:
For 100 parts by mass of the polymer component containing 40-80 parts by mass of the silane-modified polyethylene resin and 20-60 parts by mass of the polyethylene resin,
Magnesium hydroxide and / or aluminum hydroxide 30-200 parts by mass, melting point 150 ° C. or higher triazine compound 0.5-5 parts by mass, benzimidazole compound 1-10 parts by mass, zinc oxide 1-10 parts by mass, copper The gist is to contain 0.1 to 5 parts by mass of a harmful agent.

  The flame retardant composition may further contain 1 to 10 parts by mass of a phenolic antioxidant with respect to 100 parts by mass of the polymer component.

In addition, the method for producing a flame retardant resin according to the present invention includes:
A component containing a silane-modified polyethylene resin obtained by graft polymerization of a silane coupling agent to a polyethylene resin;
B component formed by blending magnesium hydroxide or / and aluminum hydroxide, a triazine compound having a melting point of 150 ° C. or higher, a benzimidazole compound, zinc oxide, and a copper damage inhibitor in a polyethylene resin,
A C component obtained by blending a polyethylene-based resin with a silane crosslinking catalyst;
The gist is to carry out water crosslinking after kneading and molding.

  In the method for producing a flame retardant resin, the component B may further contain a phenolic antioxidant.

  The gist of the insulated wire according to the present invention is that the outer periphery of the conductor is covered with an insulator formed from the flame retardant composition.

  The flame retardant composition according to the present invention is magnesium hydroxide and / or hydroxylated with respect to 100 parts by mass of a polymer component containing 40-80 parts by mass of a silane-modified polyethylene resin and 20-60 parts by mass of a polyethylene resin. 30 to 200 parts by mass of aluminum, 0.5 to 5 parts by mass of a triazine compound having a melting point of 150 ° C. or higher, 1 to 10 parts by mass of a benzimidazole compound, 1 to 10 parts by mass of zinc oxide, and 0.1 to 5 of a copper damage inhibitor By containing a part by mass, a resin film that has been cured and cross-linked can be obtained having excellent peelability, heat resistance, and flame retardancy.

  In particular, a resin after curing and crosslinking a conventional flame retardant composition not containing a triazine compound having a melting point of 150 ° C. or more by adding 0.5 to 5 parts by mass of a triazine compound having a melting point of 150 ° C. or more. Compared with the film, the resin films can be easily separated even after being left for a long time at a high temperature of 150 ° C. or higher with the surfaces of the resin films in contact with each other.

  The method for producing a flame retardant resin according to the present invention includes a component A containing a silane-modified polyethylene resin obtained by graft polymerization of a silane coupling agent to a polyethylene resin, and a polyethylene resin containing magnesium hydroxide and / or water. An aluminum oxide, a triazine compound having a melting point of 150 ° C. or higher, a benzimidazole compound, zinc oxide, a B component obtained by compounding a copper damage inhibitor, and a polyethylene resin and a silane crosslinking catalyst. A component A containing a silane-modified polyethylene resin obtained by graft-polymerizing a silane coupling agent to a polyethylene resin, and a flame retardant, by adopting a method in which the component C is kneaded and molded, followed by water crosslinking. By using the method of mixing and adding after the component B containing is separately kneaded, the moisture in the flame retardant and stabilizer, Since the silane coupling agent when manufacturing the run-modified polyethylene resin does not react, there is no possibility of inhibiting the graft reaction of polyethylene resin and a silane coupling agent. Moreover, there is no possibility that a gel-like substance is generated when producing a silane-modified polyethylene resin.

  Therefore, the external appearance of the flame-retardant resin molded product formed from the above-mentioned flame-retardant composition of the present invention is not deteriorated, the lack of cross-linking occurs, the heat resistance does not decrease, and the peelability and heat resistance are improved. An excellent flame retardant resin can be reliably produced.

  The insulated wire according to the present invention provides a flame-retardant wire having excellent heat resistance and releasability by covering the outer periphery of the conductor with an insulator formed from the above-mentioned flame-retardant composition. . In particular, even when a bundle of insulated wires is left in a high temperature environment of 150 ° C. or higher for a long period of time, an insulated wire excellent in peelability of the wire surfaces can be obtained without bonding the surfaces of the wires. .

  Hereinafter, embodiments of the present invention will be described in detail. The flame retardant composition according to the present embodiment is any one of a polymer component containing at least a silane-modified polyethylene resin and a polyethylene resin, magnesium hydroxide or aluminum hydroxide, or a mixture of magnesium hydroxide and aluminum hydroxide. An inorganic flame retardant, a triazine compound having a melting point of 150 ° C. or higher, a phenol antioxidant, a benzimidazole compound, zinc oxide, and a copper damage inhibitor.

  In the flame retardant composition of the present invention, the flame retardant resin obtained by molding and crosslinking the flame retardant composition by using a triazine compound having a melting point of 150 ° C. or higher is in a state where the resins are in contact with each other. Even after being left at a high temperature of 150 ° C. or higher for a long period of time, the resins can be peeled off satisfactorily and have releasability. It is considered that this is because the triazine compound having a melting point of 150 ° C. or higher suppresses melting and bonding of uncrosslinked portions of the polyethylene resin as a polymer component at a high temperature.

  In the present invention, having releasability means having releasability to such an extent that the resins can be easily separated after being left under the condition of 150 ° C. × 24 hours in a state where the resins are in contact with each other. Moreover, having heat resistance in the present invention means having heat resistance enough to pass a long-term heat resistance evaluation test of 150 ° C.-3000 hours of ISO 6722 standard.

  In addition, the flame retardant composition has high heat resistance due to the phenolic antioxidant, benzimidazole compound, zinc oxide, and copper damage inhibitor. The phenolic antioxidant captures radicals generated with thermal degradation in the flame retardant composition. The benzimidazole compound is presumed to suppress thermal degradation of the silane-crosslinked polyethylene by forming a supplementary cross-linking bond between the silane-crosslinked polyethylene while the sulfur atoms are affected by the action of zinc oxide and thermal degradation is in progress. Is done. Furthermore, the copper damage preventing agent captures copper ions generated from the conductor (copper wire) of the insulated wire, and suppresses thermal degradation of the insulator due to copper as a catalyst.

  The silane-modified polyethylene resin is used in the range of 40 to 80 parts by mass in 100 parts by mass of the total amount of polymer components including the silane-modified polyethylene resin and the polyethylene resin (hereinafter sometimes simply referred to as polymer component). The The silane-modified polyethylene resin is obtained by modifying a polyethylene resin with a silane coupling agent or the like. Examples of the polyethylene resin used for the silane-modified polyethylene resin include an ethylene polymer. Moreover, as said polyethylene-type resin, you may use ethylene-type copolymers, such as an ethylene-vinyl acetate copolymer and an ethylene-acrylic acid ester copolymer. These may be used alone or in combination.

  Examples of the ethylene polymer include high density polyethylene (HDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), and ultra low density polyethylene. These may be used alone or in combination. The polyethylene resin of the silane-modified polyethylene resin is preferably ultra-low density polyethylene from the viewpoint of excellent flexibility.

The silane-modified polyethylene resin preferably has a density of 0.910 g / cm ³ or less from the viewpoint of excellent flexibility. However, since the degree of crystallinity of the resin decreases as the density decreases, the density of the resin from which silane-grafted resin is suppressed from swelling with respect to gasoline (oil) and the like and gasoline resistance is improved. It is preferably 0.880 g / cm ³ or more. Therefore, the polyethylene resin used for forming the silane-modified polyethylene resin preferably has a density in the range of 0.880 to 0.910 g / cm ³ .

  As the polyethylene resin contained together with the silane-modified polyethylene resin, a non-silane-modified polyethylene resin is used. Examples of the polyethylene resin include those exemplified as the polyethylene resin of the silane-modified polyethylene resin. These can be used alone or in combination of two or more. The polyethylene resin is preferably the same type as the silane-modified polyethylene resin from the viewpoint of compatibility.

  The said polyethylene-type resin is used in the range of 20-60 mass parts in 100 mass parts of total amounts of a polymer component. When the polyethylene resin is less than 20 parts by mass in 100 parts by mass of the total amount of polymer components, the amount of flame retardant that can be taken in during kneading decreases, and the flame retardancy tends to be insufficient. On the other hand, when the polyethylene resin exceeds 60 parts by mass, the silane-modified polyethylene resin in the polymer component is relatively reduced, so that the crosslinking component is reduced and the gel fraction tends to be insufficient.

  The content of magnesium hydroxide or aluminum hydroxide used as the inorganic flame retardant is in the range of 30 to 200 parts by mass with respect to 100 parts by mass of the polymer component, and the type of flame retardant resin or insulated wire, The content can be appropriately determined depending on the size, the conductor, the structure of the insulator, and the like.

  If the inorganic flame retardant is in the range of 30 to 200 parts by mass with respect to 100 parts by mass of the polymer component, for example, sufficient flame retardancy to be required for an electric wire for automobiles is easily obtained. When the inorganic flame retardant is less than 30 parts by mass with respect to 100 parts by mass of the polymer component, sufficient flame retardancy cannot be obtained. Moreover, when it exceeds 200 mass parts, sufficient mechanical characteristics cannot be obtained.

  A triazine-based compound having a melting point of 150 ° C. or higher blended in the flame retardant composition is used for improving the peelability. With a triazine compound having a melting point of less than 150 ° C., sufficient peelability cannot be obtained.

  Examples of triazine compounds having a melting point of 150 ° C. or higher include 1,3,5-tris (3,5-di-tert-butyl-4hydroxybenzyl) -1,3,5-triazine-2,4,6. (1H, 3H, 5H) trione (melting point 226 ° C.), 1,3,5-tris [(4-tert-butyl-3-hydroxy-2,6-xylyl) methyl] -1,3,5-triazine- 2, 4, 6 (1H, 3H, 5H) trione (melting point: 162 ° C).

  In the flame retardant composition of the present invention, the content of the triazine compound having a melting point of 150 ° C. or higher is in the range of 0.5 to 5 parts by mass with respect to 100 parts by mass of the polymer component. If the content is less than 0.5 parts by mass, sufficient peelability cannot be obtained, and if it exceeds 5 parts by mass, the cost becomes high.

  The flame retardant composition of the present invention preferably contains a phenolic antioxidant. Examples of phenolic antioxidants include pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], thiodiethylenebis [3- (3,5-di-tert-butyl). -4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-tert-butyl 4-hydroxyphenyl) propionate, N, N′-hexane-1,6-diylbis [3- (3,5- Di-tert-butyl-4-hydroxyphenyl) propionamide] and the like.

  As content of the phenolic antioxidant in a flame retardant composition, it is preferable to exist in the range of 1-10 mass parts with respect to 100 mass parts of said polymer components. Heat resistance can be further improved by incorporating a phenolic antioxidant into the flame retardant composition. If the content of the phenolic antioxidant is less than 1 part by mass with respect to 100 parts by mass of the polymer component, the heat resistance improving effect may be insufficient, and if it exceeds 10 parts by mass, particularly in a high-temperature and high-humidity atmosphere. There is a possibility that it will be easy to bloom.

  Examples of the benzimidazole compound include 2-mercaptobenzimidazole, 2-mercaptomethylbenzimidazole, 4-mercaptomethylbenzimidazole, 5-mercaptomethylbenzimidazole, and zinc salts thereof. Particularly preferred are 2-mercaptobenzimidazole and its zinc salt. The benzimidazole-based compound may have a substituent such as an alkyl group at another position of the benzimidazole skeleton.

  Content of the benzimidazole type compound in a flame retardant composition exists in the range of 1-10 mass parts with respect to 100 mass parts of said polymer components. When the content of the benzimidazole compound is less than 1 part by mass, the effect of improving heat resistance is insufficient, and when it exceeds 10 parts by mass, blooming easily occurs particularly in a high temperature and high humidity atmosphere.

  Content of the zinc oxide in a flame-retardant composition exists in the range of 1-10 mass parts with respect to 100 mass parts of said polymer components. When the zinc oxide content is less than 1 part by mass, the effect of improving heat resistance is insufficient, and when it exceeds 10 parts by mass, sufficient mechanical properties cannot be obtained.

  Examples of the copper damage inhibitor include 3- (N-salicyloyl) amino-1,2,4-triazole, decamethylenedicarboxylic acid disalicyloyl hydrazide, and 2,3-bis [3- (3,5-diazole). -Tert-butyl-4-hydroxyphenyl) propionyl] propionohydrazide and the like.

  Content of the copper damage inhibitor in a flame retardant composition exists in the range of 0.1-5 mass parts with respect to 100 mass parts of said polymer components. When the content of the copper damage inhibitor is less than 0.1 parts by mass, the effect of improving heat resistance is insufficient, and when it exceeds 5 parts by mass, the effect of improving heat resistance is saturated, while in a high temperature and high humidity environment. Blooming is easier and the cost increases.

  The flame retardant composition preferably contains a silane crosslinking catalyst. Examples of the silane crosslinking catalyst include metal carboxylates such as tin, zinc, iron, lead, cobalt, barium, and calcium, titanate esters, organic bases, inorganic acids, and organic acids. Specifically, dibutyltin dilaurate, dibutyltin dimaleate, dibutyltin mercaptotide (dibutyltin bisoctylthioglycol ester salt, dibutyltin β-mercaptopropionate polymer, etc.), dibutyltin diacetate, dioctyltin dilaurate, first acetate Tin, stannous caprylate, lead naphthenate, cobalt naphthenate, barium stearate, calcium stearate, tetrabutyl ester titanate, tetranonyl titanate, dibutylamine, hexylamine, pyridine, sulfuric acid, hydrochloric acid, toluenesulfonic acid , Acetic acid, stearic acid, maleic acid and the like. Dibutyltin dilaurate, dibutyltin dimaleate, and dibutyltin mercaptide are preferable.

  The content of the silane crosslinking catalyst in the flame retardant composition is in the range of 0.005 to 0.3 parts by mass with respect to 100 parts by mass of the polymer component that is the total amount of the silane-modified polyethylene resin and the polyethylene resin. is there. The amount of the silane crosslinking catalyst is preferably 0.01 to 0.1 parts by mass with respect to 100 parts by mass of the polymer component. When the amount of the silane crosslinking catalyst is less than 0.005 parts by mass with respect to 100 parts by mass of the polymer component, the degree of crosslinking is insufficient, and when it exceeds 0.3 parts by mass, the appearance of the molded product deteriorates.

  In the flame-retardant composition according to the present invention, other additives than the above may be included as necessary within the range not impairing the characteristics of the present invention. Examples of such additives include ultraviolet absorbers, processing aids (waxes, lubricants, etc.), flame retardant aids, pigments and the like.

  In the flame retardant composition of the present invention, the flame retardant resin obtained by molding and crosslinking the flame retardant composition by using a triazine compound having a melting point of 150 ° C. or higher is in a state where the resins are in contact with each other. Even after being left at a high temperature of 150 ° C. or higher for a long period of time, the resins can be peeled off satisfactorily, and those having excellent peelability can be obtained. It is considered that this is because the triazine compound having a melting point of 150 ° C. or higher suppresses melting and bonding of uncrosslinked portions of the polyethylene resin as a polymer component at a high temperature.

  In addition, the flame retardant composition has high heat resistance due to the phenolic antioxidant, benzimidazole compound, zinc oxide, and copper damage inhibitor. The phenolic antioxidant captures radicals generated with thermal degradation in the flame retardant composition. The benzimidazole compound is presumed to suppress thermal degradation of the silane-crosslinked polyethylene by forming a supplementary cross-linking bond between the silane-crosslinked polyethylene while the sulfur atoms are affected by the action of zinc oxide and thermal degradation is in progress. Is done. Furthermore, the copper damage preventing agent captures copper ions generated from the conductor (copper wire) of the insulated wire, and suppresses thermal degradation of the insulator due to copper as a catalyst.

  The silane-modified polyethylene resin can be obtained by a method such as a graft reaction of a polyethylene resin and a silane crosslinking agent such as a silane coupling agent using a radical generator such as an organic peroxide.

  In the present invention, in order to achieve sufficient silane crosslinking, a silane-modified polyethylene resin is synthesized in advance and brought into contact with an inorganic flame retardant such as magnesium hydroxide or aluminum hydroxide. If an inorganic flame retardant, a polyethylene resin, and a silane coupling agent are kneaded at the same time, the moisture of the inorganic flame retardant reacts with the silane coupling agent, which may inhibit the graft reaction between the polyethylene resin and the silane coupling agent. is there. Further, when moisture and a silane coupling agent react to produce a gel-like substance, it appears on the surface of the resin film formed from the composition, which may deteriorate the appearance of the insulator. Further, when the silane coupling agent reacts with moisture, there is a possibility that insufficient crosslinking occurs and the heat resistance is lowered. On the other hand, by synthesizing a silane-modified polyethylene resin in advance and mixing with an inorganic flame retardant containing moisture later, the silane-modified polyethylene resin can be silane-crosslinked with a high degree of crosslinking.

  Examples of the silane coupling agent include vinyl alkoxysilanes such as vinyltrimethoxysilane, vinyltriethoxysilane, and vinyltributoxysilane, normal hexyltrimethoxysilane, vinylacetoxysilane, γ-methacryloxypropyltrimethoxysilane, Examples thereof include γ-methacryloxypropylmethyldimethoxysilane. These may be used alone or in combination of two or more.

  Examples of the radical generator include dicumyl peroxide (DCP), benzoyl peroxide, dichlorobenzoyl peroxide, di-tert-butyl peroxide, butyl peracetate, tert-butyl perbenzoate, 2,5-dimethyl-2, Examples thereof include 5-di (tert-butylperoxy) hexane. More preferred is dicumyl peroxide (DCP).

  Hereinafter, the manufacturing method of a flame-retardant resin is demonstrated. The flame retardant resin is obtained by kneading each component of the above flame retardant composition using a kneader, forming the resin into a predetermined resin shape, and water-crosslinking the molded product. It is done. The following method is preferable as the method for producing the flame retardant resin. A flame retardant composition in advance, a component A containing a silane-modified polyethylene resin obtained by graft polymerization of a silane coupling agent to a polyethylene resin, and a magnesium resin or / and aluminum hydroxide to a polyethylene resin. A B component formed by mixing and dispersing a triazine compound having a melting point of 150 ° C. or higher, a phenolic antioxidant, a benzimidazole compound, zinc oxide, and a copper damage inhibitor, and a polyethylene resin, The components are mixed and dispersed into a C component formed by dispersing and crosslinking a crosslinking catalyst, and after forming into a predetermined shape, water crosslinking is performed to perform silane crosslinking. The components A to C are preferably heated and melted and kneaded immediately before molding.

  Examples of the kneader include a Banbury mixer, a pressure kneader, a kneading extruder, a twin screw extruder, and a roll. For silane crosslinking, water crosslinking with water or steam can be used.

  In the above production method, since the silane-modified polyethylene resin and the inorganic flame retardant are separately kneaded as the A component and the B component, it is avoided that the moisture in the inorganic flame retardant reacts directly with the silane coupling agent. It is done. When preparing a silane-modified polyethylene-based resin, the graft reaction between the polyethylene-based resin and the silane coupling agent is not inhibited, and there is no possibility of generating a gel substance. Therefore, the appearance of the molded product of the flame retardant resin formed from the flame retardant composition is not deteriorated, and lack of crosslinking does not occur, so that the heat resistance is not lowered.

  The flame retardant composition of the present invention can be used for members and insulating materials used in automobiles, electronic / electrical equipment, and is particularly preferably used as a material for forming an insulating layer (covering material) of an insulated wire.

  When using a flame retardant resin obtained from a flame retardant composition as a covering material for insulated wires, after extruding a kneaded product of the above components on the outer periphery of a conductor made of copper, copper alloy, aluminum, aluminum alloy, etc. By performing silane crosslinking (water crosslinking), an insulator (covering material) made of a crosslinked flame-retardant resin can be formed.

  The insulated wire according to the present invention is one in which the outer periphery of a conductor is covered with an insulator formed from the flame retardant composition. The conductor diameter and material of the conductor are not particularly limited, and can be appropriately selected according to the use of the insulated wire. Further, the insulating coating layer made of the flame retardant composition may be a single layer or a plurality of layers of two or more layers. The thickness of the insulating coating layer is not particularly limited, and can be appropriately determined in consideration of the conductor diameter and the like.

Examples of the present invention and comparative examples are shown below.
[Test materials and preparation methods]
The test materials and preparation methods of the respective components used in the examples and comparative examples are shown.

[Component A] Silane-modified polyethylene (Silane-modified polyethylene resin)

・ Polyethylene [manufactured by DuPont Dow Elastomer Japan, trade name “engage 8003”, density 0.885 g / cm ³ ]
・ Silane coupling agent (vinyl) [made by Toray Dow Corning Co., Ltd., trade name “SZ6300”]
・ Dicumyl peroxide (DCP) [manufactured by NOF Corporation, trade name “Park Mill D”]

[Preparation of component A (silane graft batch)]
65 parts by weight of polyethylene, 0.33 parts by weight of a silane coupling agent, and 0.07 parts by weight of DCP are added to a biaxial extrusion kneader and heated and kneaded at 200 ° C. for 0.1 to 2 minutes. Modified polyethylene was prepared.

[B component]
・ Polyethylene [manufactured by DuPont Dow Elastomer Japan, trade name “engage 8003”, density 0.885 g / cm ³ ]
・ Magnesium hydroxide [Kyowa Chemical Co., Ltd., trade name “Kisuma 5”]
Triazine compound having a melting point of 150 ° C. or higher: 1,3,5-tris (3,5-di-tert-butyl-4hydroxybenzyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) Trione [BASF, trade name “Irganox 3114”, melting point 226 ° C.]
・ Phenolic antioxidant (1) [trade name “Irganox 1010” manufactured by BASF Corporation]
・ Phenolic antioxidant (2) [Adeka's product name “AO80”]
・ Phenolic antioxidant (3) [trade name “Irganox 1330” manufactured by BASF Corporation]
・ Benzimidazole compounds [made by Ouchi Shinsei Chemical Co., Ltd., trade name “NOCRACK MB”]
・ Zinc oxide [manufactured by Hakusuitec Co., Ltd., trade name "Zinc oxide 1 type"]
・ Copper damage prevention agent [manufactured by Adeka, trade name “CD-1”]

[Preparation of component B (flame retardant batch)]
Each component of component B was added to a biaxial extrusion kneader at the blending mass ratio shown in Tables 1-2, and after heat-kneading at 200 ° C. for 0.1-2 minutes, pelletized to prepare a flame retardant batch.

[C component]
・ Polyethylene [manufactured by DuPont Dow Elastomer Japan, trade name “engage 8003”, density 0.885 g / cm ³ ]
・ Silane cross-linking catalyst (dibutyltin dilaurate) [Wako Pure Chemical Industries, reagent]

[Preparation of component C (catalyst batch)]
Polyethylene and the silane cross-linking catalyst were added to a biaxial extrusion kneader at the blending mass ratio shown in Tables 1 and 2, and kneaded at 200 ° C. for 0.1 to 2 minutes, and then pelletized to prepare a catalyst batch.

[Production of insulated wires]
The silane graft batch, the flame retardant batch, and the catalyst batch were mixed with a hopper of an extruder and the temperature of the extruder was set to about 180 to 200 ° C. to perform extrusion. Extrusion coating was performed on a conductor having an outer diameter of 2.4 mm as an insulator having a thickness of 0.7 mm (coating outer diameter: 3.8 mm). Then, the water-crosslinking process was performed for 24 hours in the high-humidity high temperature tank of 60 degreeC and 90% humidity, and the insulated wire was produced.

  About the obtained insulated wire, the flame retardance, heat resistance, mechanical characteristics, and peelability were evaluated according to the following method. The results are shown in Tables 1-2.

〔Flame retardance〕
According to JASO D608-92, a 300 mm sample was prepared and a horizontal combustion test was performed. Using a Bunsen burner with a diameter of 10 mm, the tip of the reducing flame was applied for 10 seconds from the lower side of the center of the sample, and the afterflame time after gently removing the flame was measured. The case where the flame disappeared immediately was judged as “good”, the case where the afterflame time was within 30 seconds was judged as “good”, and the case where the afterflame time was over 30 seconds was judged as “failed”.

〔Heat-resistant)
A sample of 150 mm or more was prepared, placed in a constant temperature bath at 180 ° C. for 504 hours, and then wound around a mandrel having a diameter 1.5 times the wire diameter at room temperature to observe the presence or absence of cracks in the insulator. In addition, it has been found that putting in a constant temperature bath at 180 ° C. for 504 hours corresponds to the long-term heat resistance evaluation at 150 ° C. for 3000 hours according to ISO 6722 by extrapolation of the Arrhenius plot. As a result of the test, a sample with little discoloration and no cracks was evaluated as “good”, a sample without cracks was evaluated as “good”, and a sample with cracks was determined as “failed”.

[Evaluation of mechanical properties]
Based on the tensile test of JIS C 3005, the tensile test and the tensile elongation were measured. That is, the insulated wire was cut to a length of 150 mm, the conductor was removed to obtain a tubular test piece made of only an insulating coating material, and both ends of the test piece were attached to a tensile tester chuck at room temperature of 23 ° C. ± 5 ° C. Thereafter, the test piece was pulled at a pulling rate of 200 mm / min, and the load and elongation at break of the test piece were measured. Good when the tensile strength is 11 MPa or more and elongation is 200% or more, “Good”, when the tensile strength is 10 MPa or more and 150% or more is passed, “Good”, and when the tensile strength is less than 10 MPa or less than 150%, "

[Evaluation of peelability]
A tape of two 100 mm wires wound with tape was left under conditions of 150 ° C. × 24 hours, and then the tape was removed and the two wires were peeled off. A sample that immediately peeled off and had almost no adhesion marks was rated as “Excellent”, a sample that peeled off but had a sparse adhesion mark was evaluated as “Good”, and a sample that was difficult to peel off and had an adhesion track all over was rated as “Fail”.

  As shown in Table 1, the insulated wires according to Examples 1 to 10 are all silane-modified polyethylene resin, polyethylene resin, inorganic flame retardant, triazine compound having a melting point of 150 ° C. or higher, benzimidazole compound, oxidation Since zinc and a copper damage inhibitor are contained within a predetermined range, the results of good or pass were obtained for all the properties of flame retardancy, heat resistance, mechanical properties, and peelability.

  On the other hand, as shown in Table 2, since the insulated wires of Comparative Examples 1 to 7 do not have the configuration of the present invention, all the properties of flame retardancy, heat resistance, mechanical properties, and peelability are good or The result of passing was not obtained. That is, since Comparative Example 1 did not contain a triazine compound having a melting point of 150 ° C. or higher, the peelability was unacceptable. Since Comparative Example 2 did not contain a benzimidazole compound, the heat resistance was unacceptable. Since Comparative Example 3 did not contain zinc oxide, the heat resistance was unacceptable. Since Comparative Example 4 did not contain a copper damage inhibitor, the heat resistance was unacceptable. Since Comparative Example 5 did not contain magnesium hydroxide, the flame retardancy and heat resistance were unacceptable. Since the comparative example 3 had little content of the silane modified polyethylene in a polymer component, heat resistance was disqualified.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention.

Claims (5)

For 100 parts by mass of the polymer component containing 40-80 parts by mass of the silane-modified polyethylene resin and 20-60 parts by mass of the polyethylene resin,
Magnesium hydroxide and / or aluminum hydroxide 30-200 parts by mass, melting point 150 ° C. or higher triazine compound 0.5-5 parts by mass, benzimidazole compound 1-10 parts by mass, zinc oxide 1-10 parts by mass, copper Containing 0.1 to 5 parts by mass of a harmful agent ,
The triazine compound is 1,3,5-tris (3,5-di-tert-butyl-4hydroxybenzyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) trione Or 1,3,5-tris [(4-tert-butyl-3-hydroxy-2,6-xylyl) methyl] -1,3,5-triazine-2,4,6 (1H, 3H, 5H) Trion,
The flame retardant composition, wherein the benzimidazole compound is a mercaptobenzimidazole compound .   The flame retardant composition according to claim 1, further comprising 1 to 10 parts by mass of a phenolic antioxidant based on 100 parts by mass of the polymer component. A method for producing a flame retardant resin using the flame retardant composition according to claim 1,
A component containing a silane-modified polyethylene resin obtained by graft polymerization of a silane coupling agent to a polyethylene resin;
B component formed by blending magnesium hydroxide or / and aluminum hydroxide, a triazine compound having a melting point of 150 ° C. or higher, a benzimidazole compound, zinc oxide, and a copper damage inhibitor in a polyethylene resin,
A C component obtained by blending a polyethylene-based resin with a silane crosslinking catalyst;
A method for producing a flame retardant resin, characterized in that water crosslinking is performed after kneading and molding.   The method for producing a flame-retardant resin according to claim 3, wherein the component B is further blended with a phenolic antioxidant.   An insulated wire, wherein the outer periphery of the conductor is covered with an insulator formed from the flame retardant composition according to claim 1.