WO2016175076A1

WO2016175076A1 - Non-halogen flame-resistant resin composition and insulated electric wire

Info

Publication number: WO2016175076A1
Application number: PCT/JP2016/062259
Authority: WO
Inventors: 太郎藤田; 西川　信也; 智山崎; 裕之大川; 堀　賢治
Original assignee: 住友電気工業株式会社
Priority date: 2015-04-28
Filing date: 2016-04-18
Publication date: 2016-11-03
Also published as: JPWO2016175076A1; CN106414593A

Abstract

Provided are: a non-halogen flame-resistant resin composition having excellent flame resistance, heat resistance, cold resistance, oil resistance, and mechanical strength such as tensile mechanical characteristics and abrasion resistance, whereby an insulating coating can be formed in which the abovementioned characteristics are balanced to a high degree, the non-halogen flame-resistant resin composition containing 1-20 parts by mass of silicone oil having a viscosity of 3000 mPa∙s or less, 100-250 parts by mass of a metal hydroxide, and 100 parts by mass of a polyolefin resin containing a polyethylene having a density of 0.925-0.945 and a melting point (Tm) of 120-130°C measured by DSC, an ethylene-vinyl acetate copolymer, and an anhydrous maleic acid-modified ethylene α-olefin copolymer having a melting point of 60°C or less measured by DSC in a predetermined composition range; and an insulated electric wire having an insulating coating formed using the non-halogen flame-resistant resin composition, the insulated electric wire being suitable for use in a harness or the like for an automobile or a railroad vehicle.

Description

Non-halogen flame retardant resin composition and insulated wire

The present invention relates to a non-halogen flame retardant resin composition suitable as a material for forming an insulation coating of a harness for automobiles and railway vehicles, and an insulated wire provided with an insulation coating formed from the non-halogen flame retardant resin composition.

Insulated wires such as harnesses for automobiles and railway vehicles are subject to temperature changes from cold to high temperatures and severe vibrations, and are also exposed to oils such as lubricating oil, and may be exposed to heat generation and fire of equipment. . For this reason, the insulation coating (insulation layer) has flame resistance, heat resistance, cold resistance (low temperature characteristics), oil resistance, tensile mechanical characteristics, Regarding mechanical strength such as wear resistance, it is required to satisfy predetermined standards, and ISO standards that are international standards, EN standards that are European standards, and the like are defined. In consideration of environmental problems, especially in railway applications, the insulation coating is required to contain no halogen (non-halogen, halogen-free) in order to prevent passengers from evacuating due to smoke during a fire. .

In Patent Document 1, a conductor made of a non-halogen resin composition having excellent flame retardancy and heat resistance is coated on a conductor, and used as a railway vehicle wire or a railway vehicle cable (hereinafter referred to as “electric wire”). Is used in the meaning including the cable). The resin composition contains 100 to 250 parts by mass of a metal hydroxide and 3 to 50 parts by mass of amorphous silica with respect to 100 parts by mass of a polyolefin-based resin as a base polymer. Having a specific gravity of 0.1 to 2.3 g / cm ^{3 and} a specific surface area of 15 to 50 m ² / g, the polyolefin resin comprises 10 to 40% by mass of maleic anhydride-modified ethylene-α-olefin copolymer and Melt mass flow rate (melt flow rate: MFR) 2.0 (g / 10 min) or less, characterized in that it contains 60 to 90% by mass of polyethylene having a density of 0.900 to 0.925 g / cm ³ .

Patent Document 2 discloses a non-halogen crosslinkable resin composition that is a material of a cross-linked molded body having flame resistance and excellent mechanical properties, and excellent in oil resistance, cold resistance, and room temperature storage, and the cross-linked molded body An insulated electric wire for vehicles provided with a coating layer made of is disclosed. This non-halogen crosslinkable resin composition comprises one or more kinds of ethylene-vinyl acetate copolymer (EVA) and an acid-modified polyolefin resin having a glass transition point (Tg) by DSC of −55 ° C. or lower within a predetermined range. The EVA contains 100 to 250 parts by mass of a metal hydroxide with respect to 100 parts by mass of the base polymer, and at least one of the EVA has a melting point of 70 ° C. or higher by the DSC method. The content (VA amount) is 25 to 50% by mass.

Japanese Patent No. 5617903 Japanese Patent Laid-Open No. 2015-21120

In recent years, the application of EN standards has been expanded for insulated electric wires for vehicles, and passing of the vertical combustion test is required. In addition, in order to be used as a power cable, it must pass tests such as flame retardancy, heat resistance, oil resistance, and low temperature characteristics specified in EN50264-3-1. In addition to these test items, it may be desired to pass a durability test such as a strict wear resistance test that assumes a use environment that is constantly exposed to vibration and the like. In particular, a cable for a railway vehicle is required to be light in weight for speeding up and saving energy, so that it is required to pass the durability test even when the insulation coating is thin.

Durability such as wear resistance can be improved if the insulating coating is formed of a highly crystalline resin. In this case, however, the EN standard low temperature characteristics are likely to be rejected. Thus, there is no existing insulated wire that satisfies all of the above requirements.

The present invention is excellent in mechanical strength such as flame resistance, heat resistance, cold resistance (low temperature characteristics), oil resistance, tensile mechanical characteristics, wear resistance, etc. An object of the present invention is to provide a non-halogen flame retardant resin composition used for forming the above.

In the present invention, the non-halogen flame retardant resin composition is used as a forming material, and it has flame resistance, heat resistance, low temperature characteristics (cold resistance), oil resistance, and mechanical strength such as tensile mechanical characteristics and wear resistance. An object of the present invention is to provide an insulated wire that is excellent and has an insulation coating that balances them at a high level, and that is suitably used as a harness for automobiles or railway vehicles.

The first aspect of the present invention is:
100 parts by mass or more and 250 parts by mass or less of metal hydroxide, and 1 part by mass or more and 20 parts by mass or less of silicone oil having a viscosity at 25 ° C. of 3000 mPa · s or less with respect to 100 parts by mass of polyolefin resin. ,
The polyolefin resin is
30 mass% or more and 85 mass% or less of polyethylene whose melting point (Tm) by DSC method is 120 ° C. or more and 130 ° C. or less and whose density is 0.925 or more and 0.945 or less,
Ethylene-vinyl acetate copolymer (EVA) 10 mass% or more and 60 mass% or less, and maleic anhydride-modified ethylene α-olefin copolymer having a melting point of 60 ° C. or less by DSC method is 5 mass% or more, 30 It is a non-halogen flame retardant resin composition containing at most mass%.

The second aspect of the present invention has a conductor and an insulating coating covering the conductor,
The insulating coating is a non-halogen flame retardant insulated wire made of a crosslinked product of the non-halogen flame retardant resin composition of the first aspect.

A third aspect of the present invention has a conductor and an insulation coating,
The insulating coating has an inner layer covering the conductor and an outer layer covering the inner layer;
The inner layer is made of polyethylene or a composition mainly composed of polyethylene,
The outer layer is a non-halogen flame retardant insulated wire made of a crosslinked product of the non-halogen flame retardant resin composition of the first aspect.

According to the first aspect of the present invention, it can be used as a material for insulation coating of insulated wires, satisfying test items such as flame retardancy, heat resistance, oil resistance, low temperature characteristics and the like specified in EN50264-3-1, Insulation that has high wear resistance even at a thin wall and balances mechanical strength such as flame resistance, heat resistance, cold resistance (low temperature characteristics), oil resistance, tensile mechanical characteristics, and wear resistance at a high level. A non-halogen flame retardant resin composition capable of forming a coating is provided.

According to the second aspect of the present invention, it satisfies the test items such as flame retardancy, heat resistance, oil resistance, and low temperature characteristics specified in EN50264-3-1 and has high wear resistance, and flame retardancy, Equipped with an insulation coating that balances mechanical strength such as heat resistance, low temperature characteristics (cold resistance), oil resistance, tensile mechanical characteristics, and wear resistance at a high level, and is suitable for use as a harness for automobiles or railway vehicles A non-halogen flame retardant insulated wire is provided.

According to the third aspect of the present invention, the test items such as flame retardancy, heat resistance, oil resistance, and low temperature characteristics specified in EN50264-3-1 are satisfied, and flame retardancy, heat resistance, low temperature characteristics (cold resistance) ), Oil resistance, and insulation coating that balances mechanical strength such as tensile mechanical properties and wear resistance at a high level, and high durability such as wear resistance even when the insulation coating is thin. Provided is a non-halogen flame retardant insulated wire that has high insulation characteristics and is suitably used as a harness for automobiles or railway vehicles.

It is sectional drawing of an example of the insulated wire of this invention (3rd aspect).

Next, a mode for carrying out the present invention will be specifically described. In addition, this invention is not limited to the following form and the below-mentioned Example, All the changes within the range of a claim and the meaning equivalent to a claim are included.

[First Embodiment (Non-Halogen Flame Retardant Resin Composition)]
The first aspect of the present invention is:
100 parts by mass or more and 250 parts by mass or less of metal hydroxide, and 1 part by mass or more and 20 parts by mass or less of silicone oil having a viscosity at 25 ° C. of 3000 mPa · s or less with respect to 100 parts by mass of polyolefin resin. ,
The polyolefin resin is
30 mass% or more and 85 mass% or less of polyethylene whose melting point (Tm) by DSC method is 120 ° C. or more and 130 ° C. or less and whose density is 0.925 or more and 0.945 or less,
Ethylene-vinyl acetate copolymer (EVA) 10 mass% or more and 60 mass% or less, and maleic anhydride-modified ethylene α-olefin copolymer having a melting point of 60 ° C. or less by DSC method is 5 mass% or more, 30 It is a non-halogen flame retardant resin composition containing at most mass%.

As a result of intensive studies to solve the above problems, the present inventor is a non-halogen flame retardant resin composition containing a polyolefin resin and a metal hydroxide,
Contains a predetermined amount of silicone oil whose viscosity is within a predetermined range,
As the polyolefin resin, a material containing EVA and maleic anhydride-modified ethylene α-olefin copolymer in a predetermined range composition in polyethylene as a base polymer,
By using a non-halogen flame retardant resin composition in which the polyethylene is highly crystalline, that is, polyethylene having a melting point of 120 ° C. or higher and 130 ° C. or lower and a density of 0.925 or higher and 0.945 or lower,
Satisfies test items such as flame retardancy, heat resistance, oil resistance, and low temperature characteristics specified in EN50264-3-1 and has high wear resistance, and also flame resistance, heat resistance, cold resistance (low temperature characteristics) The present inventors have found that an insulating coating can be formed that balances mechanical strength such as oil resistance, tensile mechanical properties, and wear resistance at a high level. For example, if an insulating coating is formed using highly crystalline polyethylene, it is possible to improve the wear resistance, etc., but the low-temperature deterioration that occurs in this case can be prevented by adding silicone oil. It was found that both durability and low temperature that satisfy the above conditions can be achieved.

(Polyolefin resin)
1) Polyethylene Polyethylene, which is a base polymer constituting the polyolefin resin, is highly crystalline polyethylene. Specifically, the melting point (Tm) by DSC method is 120 ° C. or higher and 130 ° C. or lower, and the density is in the range of 0.925 or higher and 0.945 or lower. By using polyethylene having high crystallinity, excellent wear resistance can be obtained. When polyethylene having a melting point (Tm) of less than 120 ° C. and a density of less than 0.925 is used, abrasion resistance that satisfies the standard cannot be obtained. On the other hand, when a polyethylene having a melting point (Tm) exceeding 130 ° C. and a density exceeding 0.945 is used, the cold resistance is lowered and it is difficult to meet the standards required in recent years. Further, the melt flow rate (MFR) is preferably larger than 0.1 g / 10 min and smaller than 5.0 g / 10 min. If the MFR is 0.1 g / 10 min or less, the appearance may be roughened during extrusion, and if it is 5.0 g / 10 min or more, sufficient tensile strength may not be obtained.

2) Ethylene-vinyl acetate copolymer (EVA)
The content of EVA is in the range of 10% by mass or more and 60% by mass or less based on the total mass of polyethylene, EVA and maleic anhydride-modified ethylene α-olefin copolymer. When the content of EVA is less than 10% by mass, the cold resistance is lowered and it is difficult to satisfy the standards required in recent years. On the other hand, when the content of EVA exceeds 60% by mass, the wear resistance decreases, and the wear resistance that satisfies the standard cannot be obtained.

The EVA used here is preferably one having a VA amount (vinyl acetate content) in the range of more than 20% by mass and less than 40% by mass. Moreover, the melting point (Tm) by DSC method is preferably higher than 40 ° C and lower than 85 ° C. If the EVA VA content is 20% by mass or less or the melting point is 85 ° C. or more, cold resistance may be deteriorated. If the EVA VA content is 40% by mass or more or the melting point is 40 ° C. or less, the pellets become sticky. In the summer, pellets may be blocked, making extrusion difficult. Furthermore, it is preferable that MFR is larger than 0.1 g / 10min and smaller than 5.0 g / 10min. If the MFR is 0.1 g / 10 min or less, the appearance may be roughened during extrusion, and if it is 5.0 g / 10 min or more, sufficient tensile strength may not be obtained. One type of EVA may be used alone, or two or more types may be used in combination.

3) Maleic anhydride-modified ethylene α-olefin copolymer A maleic anhydride-modified ethylene α-olefin copolymer is obtained by grafting maleic anhydride onto an ethylene α-olefin copolymer. It can be obtained by adding a peroxide to the α-olefin copolymer and kneading with a twin screw extruder or the like. Examples of the α-olefin used here include butene, propylene, and octene.

The maleic anhydride-modified ethylene-α-olefin copolymer has a melting point of 60 ° C. or less by DSC method. When the DSC method has a melting point exceeding 60 ° C., the cold resistance is lowered, and it becomes difficult to satisfy the standards required in recent years.

The content of the maleic anhydride-modified ethylene-α-olefin copolymer is 5% by mass or more and 30% by mass or less based on the total mass of polyethylene, EVA and maleic anhydride-modified ethylene α-olefin copolymer. Range. When the amount is less than 5% by mass, the cold resistance is lowered and it becomes difficult to satisfy the standards required in recent years. On the other hand, if it exceeds 30% by mass, the mechanical strength such as wear resistance and tensile strength is lowered, and the wear resistance and tensile strength satisfying the standard cannot be obtained.

(Metal hydroxide (flame retardant))
The non-halogen flame retardant resin composition of the first aspect contains a metal hydroxide as a flame retardant, in an amount of 100 parts by mass to 250 parts by mass with respect to 100 parts by mass of the polyolefin resin. When the addition amount is less than 100 parts by mass, sufficient flame retardancy cannot be obtained, and when it is more than 250 parts by mass, mechanical strength such as tensile strength is lowered. Moreover, cold resistance falls. The addition amount of the metal hydroxide is preferably 130 parts by mass or more and 220 parts by mass or less, and more preferably 150 parts by mass or more and 200 parts by mass or less.

Examples of the metal hydroxide include magnesium hydroxide, aluminum hydroxide, calcium hydroxide and the like. Of these, magnesium hydroxide and aluminum hydroxide are preferable. 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 stearic acid and calcium stearate, fatty acid metal salts, and the like. Further, an appropriate amount of metal hydroxide other than these may be added.

(Silicone oil)
The halogen-free flame retardant resin composition of the first aspect contains 1 to 20 parts by mass of silicone oil having a viscosity at 25 ° C. of 3000 mPa · s or less with respect to 100 parts by mass of the polyolefin resin. It is characterized by. By containing silicone oil, flame retardancy can be improved, and excellent flame retardancy even when the content of metal hydroxide is about 180 parts by mass with respect to 100 parts by mass of the polyolefin resin. Is obtained. In addition, it is possible to prevent a decrease in cold resistance caused by the use of highly crystalline polyethylene. When the content of the silicone oil is less than 1 part by mass, the flame retardancy becomes insufficient, and the decrease in cold resistance cannot be prevented sufficiently. When the content of the silicone oil exceeds 20 parts by mass, the wear resistance decreases.

The silicone oil used has a viscosity at 25 ° C. of 3000 mPa · s or less. When a silicone oil having a viscosity at 25 ° C. exceeding 3000 mPa · s is used, even if the content is in the range of 1 to 20 parts by mass, the flame retardancy becomes insufficient, and the decrease in cold resistance can be prevented. Can not.

Silicone oil is a silicone oil having a main skeleton of a siloxane bond, and is usually a linear structure silicone having a siloxane bond of about 2000 or less. As the silicone oil, a silicone oil modified with an alkyl group, an ester group, a vinyl group, a carboxyl group, an epoxy group, a hydroxyalkyl group or an amino group is preferable because it can be easily adapted to a resin or a metal hydroxide. Therefore, the non-halogen flame retardant resin composition according to the first aspect, in which the silicone oil is a modified silicone oil, is provided as a preferred aspect.

As a preferable aspect of the first aspect, in addition to the essential components, spherical silica is added in an amount of 1 part by weight or more and less than 35 parts by weight, more preferably 3 parts by weight or more, 30 parts by weight with respect to 100 parts by weight of the polyolefin resin. A non-halogen flame retardant resin composition containing not more than part by mass is provided. By containing spherical silica, the wear resistance can be further improved. When the content of spherical silica is less than 1 part by mass, a sufficient effect of improving wear resistance cannot be obtained, and when it is 35 parts by mass or more, cold resistance is insufficient.

Spherical silica means silica whose primary particles are spherical. As the spherical silica, those having a primary particle diameter of 100 μm or more are preferable. When silica with primary particles in a chain form is used instead of spherical silica, the wear resistance is improved, but the cold resistance is lowered, and even if the content is less than 35 parts by mass, sufficient cold resistance is not I can't get it.

The non-halogen flame retardant resin composition of the first aspect further includes a crosslinking aid, an antioxidant, a lubricant, a colorant (coloring pigment, etc.), a softening agent, as necessary, within a range that does not impair the spirit of the invention. It is possible to add additives such as plasticizers, inorganic fillers, compatibilizers, stabilizers and carbon black. Further, in order to further improve the flame retardancy, flame retardants and flame retardant aids other than the above metal hydroxides may be added within the range not impairing the gist of the present invention.

By subjecting the non-halogen resin composition of the first aspect to crosslinking, the mechanical strength of the molded body of the resin composition is improved. As the crosslinking method, an electron beam crosslinking method in which an electron beam is irradiated after molding, or a chemical crosslinking in which a crosslinking agent is blended in advance in the resin composition and then crosslinked by heating after molding is employed.

(Preparation of non-halogen resin composition)
In the non-halogen resin composition of the first aspect, the constituent materials are mixed using a known melt mixer such as a roll mixer, a single screw kneading extruder, a twin screw kneading extruder, a pressure kneader, or a Banbury mixer. Can be prepared.

[Second aspect (insulated wire)]
The second aspect of the present invention has a conductor and an insulating coating covering the conductor,
The insulating coating is a non-halogen flame retardant insulated wire made of a crosslinked product of the non-halogen flame retardant resin composition of the first aspect.

This insulated wire satisfies the test items such as flame retardancy, heat resistance, oil resistance, and low temperature characteristics specified in EN50264-3-1, has high wear resistance, and has flame resistance, heat resistance, low temperature. It has an insulation coating that balances mechanical strength such as properties (cold resistance), oil resistance, tensile mechanical properties, and wear resistance at a high level. Therefore, the electric wire or cable is preferably used as a harness or the like for automobiles or railway vehicles.

(conductor)
Examples of the conductor constituting the insulated wire of the second aspect include copper and aluminum having excellent conductivity. The conductor may be a single wire or a stranded wire of a plurality of strands.

(Insulation coating)
The insulating coating constituting the insulated wire of the second aspect is a crosslinked product of the non-halogen flame retardant resin composition of the first aspect. The insulating coating is formed by extruding the non-halogen resin composition of the first aspect so as to cover the surface of the conductor on the wire using a known extruder such as a melt extruder, and then the non-halogen flame-retardant resin composition. It can be formed by crosslinking a polyolefin resin constituting the product. By crosslinking the polyolefin resin, the mechanical strength such as tensile strength and abrasion resistance of the insulating coating is improved.

As a method of crosslinking the polyolefin resin, chemical crosslinking in which a crosslinking agent such as a peroxide is previously blended in the resin composition and then heated and crosslinked after the molding may be considered, but a method of irradiating the insulating coating with radiation ( Resin irradiation crosslinking) is preferred. Examples of the radiation used for irradiation crosslinking of the resin include electron beam, X-ray, γ-ray, and particle beam. The electron beam generator is low in running cost, can produce a high-power electron beam, and is easy to control. Therefore, an electron beam is preferably used in radiation.

The thickness of the insulating coating (insulating layer) can be appropriately selected within a range in which desired insulating properties and mechanical strength can be obtained according to the conductor diameter and the use of the insulated wire. When used in harnesses for automobiles and railway vehicles, they are often covered with a thickness of 0.2 mm or more.

[Third aspect (insulated wire)]
A third aspect of the present invention has a conductor and an insulation coating,
The insulating coating has an inner layer covering the conductor and an outer layer covering the inner layer;
The inner layer is made of polyethylene or a composition mainly composed of polyethylene,
The outer layer is a non-halogen flame retardant insulated wire made of a crosslinked product of the non-halogen flame retardant resin composition of the first aspect. This non-halogen flame retardant insulated wire satisfies the test items such as flame retardancy, heat resistance, oil resistance, and low temperature characteristics specified in EN50264-3-1 and is also flame retardant, heat resistance, low temperature characteristics (cold resistance) Insulation coating that balances mechanical strength such as oil resistance, tensile mechanical properties, and wear resistance at a high level, and has high durability such as wear resistance even when the insulation coating is thin. In addition, it has high insulation characteristics. Therefore, it is an electric wire or cable suitably used as a harness or the like for automobiles or railway vehicles.

(conductor)
This is the same as the conductor of the insulated wire of the second aspect.

(Insulation coating)
1) Inner layer The inner layer is made of polyethylene or a composition mainly composed of polyethylene. The composition mainly composed of polyethylene means a composition composed of only polyethylene or a resin component containing 50% by mass or more, preferably 80% by mass or more of polyethylene and other components such as a flame retardant. Other components such as antioxidants can be added to polyethylene as necessary within the range not impairing the gist of the invention.

By providing the inner layer, even if the outer layer is thin, mechanical strength such as high insulation resistance and excellent wear resistance can be imparted to the insulating coating. That is, by providing the inner layer, the outer layer can be thinned and the insulating coating can be reduced in weight.

The inner layer is made of polyethylene or a composition mainly composed of polyethylene (which may contain other components added as necessary) on a conductor line using a known extruder such as a melt extruder. It can be formed by extrusion molding so as to be coated. As polyethylene, from the viewpoint that it can be extrusion coated with a thin wall, it is preferable that MFR (190 ° C. 2.16 kgf) is in the range of 0.5 g / 10 min or more and 5.0 g / 10 min or less, and wear resistance From this point of view, the density is preferably 0.94 g / cm ³ or more.

As a composition mainly composed of polyethylene or polyethylene, which is a material for forming the inner layer, a resin composition containing polyethylene and 5 parts by mass or more and 200 parts by mass or less of aluminum silicate with respect to 100 parts by mass of the polyethylene is preferable. By forming the inner layer, the toxicity index (ITC) indicating the toxicity of the combustion gas generated when the insulating coating is burned may increase, but aluminum silicate is contained in an amount of 5 parts by mass or more with respect to 100 parts by mass of polyethylene. By suppressing the increase in the toxicity index (ITC), the standard is satisfied (passes the combustion gas toxicity test). When magnesium hydroxide is used instead of aluminum silicate, the effect of suppressing the toxicity index (ITC) cannot be obtained, and the effect of improving the insulation resistance by providing the inner layer cannot be obtained.

When the amount of aluminum silicate exceeds 200 parts by mass with respect to 100 parts by mass of polyethylene, the tensile strength and particularly the tensile elongation is lowered and may become out of specification, so 200 parts by mass or less is preferable. Therefore, as a preferred embodiment of the third embodiment, the non-halogen flame retardant resin composition, wherein the inner layer is made of a resin composition containing 5 parts by mass or more and 200 parts by mass or less of aluminum silicate with respect to 100 parts by mass of polyethylene and the polyethylene. There is provided a non-halogen flame retardant insulated wire comprising a crosslinked product of

2) Outer layer The outer layer is made of a crosslinked product of the non-halogen flame retardant resin composition of the first aspect. The outer layer was formed by extruding the non-halogen resin composition of the first aspect using a known extruder such as a melt extruder so as to cover the surface of the inner layer of the conductor on which the inner layer was formed. Then, it can form by bridge | crosslinking the polyolefin resin which comprises a non-halogen flame retardant resin composition. By crosslinking the polyolefin resin as described above, the mechanical strength such as tensile strength and abrasion resistance of the insulating coating is improved.

3) Thickness of inner layer and outer layer The thickness of the entire insulation coating can be appropriately selected within a range in which desired insulating properties and mechanical strength can be obtained according to the conductor diameter, use of the insulated wire, and the like. When used in harnesses for automobiles and railway vehicles, they are often covered with a thickness of 0.2 mm or more. The ratio of the thickness of the inner layer to the outer layer is not particularly limited, but when used for the harness of automobiles and railway vehicles, the thickness of the inner layer is preferably 0.03 mm or more in order to ensure sufficient insulation, and flame retardancy Is preferably 0.1 mm or less.

(Structure of insulated wire of the third aspect)
FIG. 1 is a cross-sectional view of an example of the insulated wire of the third aspect. In the figure, 1 represents a conductor, 2 represents an inner layer covering the conductor surface, and 3 represents an outer layer. 4 represents an insulated wire.

[1] Constituent material for insulation coating (constituent material for non-halogen resin composition)
First, each material used in the following Experiments 1 to 40 is shown below.

(Polyolefin resin)
1) Polyethylene Evolue SP2320 (manufactured by Prime Polymer Co., Ltd.): Melting point (representing melting point Tm by DSC method, the same applies hereinafter) 118 ° C., density 0.920, MFR 1.9 (“polyethylene-1” in the table) Expressed as)
Evolu SP2520 (manufactured by Prime Polymer Co., Ltd.): melting point 122 ° C., density 0.925, MFR 1.9 (indicated in the table as “polyethylene-2”)
DGDN3364 (manufactured by NUC): melting point 129 ° C., density 0.945, MFR 0.75 (referred to as “polyethylene-3” in the table)
Hi-Zex 5000S (manufactured by Prime Polymer Co., Ltd.): melting point 131 ° C., density 0.950, MFR 0.82 (referred to as “polyethylene-4” in the table)
Sumikasen C215 (manufactured by Sumitomo Chemical Co., Ltd.): LDPE, melting point 110 ° C., density 0.920, MFR 1.4 (in the table, represented as “polyethylene-5”)

2) Ethylene-vinyl acetate copolymer (EVA)
UBE polyethylene V322 (manufactured by Ube Maruzen Polyethylene): 22% VA

3) Maleic anhydride-modified ethylene α-olefin copolymer / Tuffmer MH5020 (manufactured by Mitsui Chemicals): Melting point 50 ° C. or less / Toughmer MH7020 (manufactured by Mitsui Chemicals): Melting point 55 ° C.
・ Tuffmer MA8510 (Mitsui Chemicals): melting point 66 ° C.

(Metal hydroxide (flame retardant))
・ Magnesium hydroxide: Magseeds S-6 (manufactured by Kamishima Chemical Co., Ltd.)
Aluminum hydroxide: Martinal OL-104 LEO (Albemarle)

(silica)
Spherical silica: Sidistar U (manufactured by Elchem Japan): specific gravity 2.2 g / cm ³ , specific surface area 40 m ² / g
Chain silica: Aerosil RX200 (manufactured by Nippon Aerosil Co., Ltd.): specific gravity 2.2 g / cm ³ , specific surface area 140 m ² / g

(Silicone oil)
Ester-modified silicone oil: TSF410 (manufactured by MOMENTIVE): Viscosity (25 ° C.) 30 mPa · s (indicated in the table as “TSF410”)
Vinyl-modified silicone oil: Tegomer V-Si 4022 (manufactured by EVONIK): Viscosity (25 ° C.) 1500 mPa · s (shown as “V-Si” in the table)
Carboxyl-modified silicone oil: Tegomer C-Si 2342 (manufactured by EVONIK): Viscosity (25 ° C.) 500 mPa · s (shown as “C-Si” in the table)
Epoxy-modified silicone oil: Tegomer E-Si 2330 (manufactured by EVONIK): Viscosity (25 ° C.) 500 mPa · s (shown as “E-Si” in the table)
Alkyl-modified silicone oil: TSF4421 (manufactured by MOMENTIVE): Viscosity (25 ° C.) 500 mPa · s (represented as “TSF4421” in the table)
Hydroxyalkyl-modified silicone oil: Tegomer H—Si 2311 (manufactured by EVONIK): Viscosity (25 ° C.) 100 mPa · s (shown as “H—Si” in the table)
Amino-modified silicone oil: Tegomer A-Si 2322 (manufactured by EVONIK): Viscosity (25 ° C.) 35 mPa · s (shown as “A-Si” in the table)
Amino-modified silicone oil: BY16-208 (manufactured by Toray Dow Corning Silicone): Viscosity (25 ° C.) 3000 mPa · s (shown as “BY16” in the table)
Amino-modified silicone oil: FZ-3785 (manufactured by Toray Dow Corning Silicone): Viscosity (25 ° C.) 4000 mPa · s (shown as “FZ” in the table)

(Other ingredients)
Aluminum silicate: Burgess # 30 (manufactured by Shiroishi Calcium)
Crosslinking aid: Trimethylolpropane trimethacrylate (TMPTMA): Multifunctional monomer Adekastab AO-60 (ADEKA): Hindered phenol antioxidant Adekastab AO-503 (ADEKA): Thioether oxidation Inhibitor / Lubricant: Stearic acid / Color pigment: Seest 3 (manufactured by Tokai Carbon Co., Ltd.): Average particle size 28 nm

[2] Production of insulated wire Preparation of non-halogen resin composition pellets In the formulations (units: parts by mass) shown in the column of resin composition prescription for insulation coating (outer layer) preparation in Tables 1 to 8, 5 parts by mass of a crosslinking aid (TMPTMA), ADK STAB AO Add 2 parts by weight of -60, 0.5 parts by weight of ADK STAB AO-503, 0.5 parts by weight of lubricant and 2 parts by weight of color pigment, and use a twin screw extruder (45 mmφ, L / D = 42) Then, the mixture was melt-mixed at a cylinder temperature of 160 ° C. and a screw rotation speed of 200 rpm, melt-extruded into a strand shape, then cooled and cut to produce pellets of a non-halogen resin composition.

2. Production of insulated wires in Experiments 1 to 20 and Experiments 27 to 40 Using the non-halogen resin composition pellets produced above and a single screw extruder (30 mmφ, L / D = 24), the cross-sectional area was 0.96 mm ² . An insulating coating was extrusion coated on a conductor (19 strands of tin-plated annealed copper wire TA with a diameter of 0.254 mm: TA19 / 0.254). After cooling, an electron beam was irradiated at 150 kGy to crosslink the resin to produce an insulated wire. In addition, the thickness of the insulation coating was 0.665 mm, and the outer diameter of the insulated wire was 2.6 mm.

3. Preparation of insulated wires in Experiments 21 to 26 In the prescription (unit: parts by mass) shown in the column of the resin composition prescription for inner layer preparation in Table 5, 2 parts by mass of Adekastab AO-60 and 0. 5 parts by mass were added, and pellets of the resin composition for the inner layer were prepared by the same conditions and methods as those for the preparation of the non-halogen resin composition pellets. The pellet and a single-screw extruder (30mmφ, L / D = 24 ) with (19 pieces of tin-plated annealed copper wire TA of 0.254mmφ twist: TA19 / 0.254) conductor cross-sectional area 0.96 mm ² of An extrusion coating was performed on the surface to form an inner layer having a thickness of 0.05 mm.

The outer layer (insulating coating) was extrusion coated on the surface of the formed inner layer using the non-halogen resin composition pellets prepared above and a single screw extruder (30 mmφ, L / D = 24). After cooling, an electron beam was irradiated at 150 kGy to crosslink the resin to produce an insulated wire. The outer layer had a thickness of 0.615 mm, the total thickness of the inner layer and the outer layer was 0.665 mm, and the outer diameter of the insulated wire was 2.6 mm.

[3] Evaluation of insulated wires The following evaluations (tests and measurements) were performed on the insulated wires produced as described above. The results are shown in Tables 1-8.

(Tensile test)
The insulation coating after the conductor was drawn out from the insulated wire produced as described above was pulled at 200 mm / min by the method defined in JIS C3005, and the tensile strength and tensile elongation were measured. And, the tensile strength was ≧ 10 MPa and the tensile elongation was ≧ 150%, and those with less than 10 MPa and less than 150% were rejected. In the table, “A” indicates pass and “C” indicates failure.

(Measurement of insulation resistance)
Implemented in accordance with JIS C3667. A voltage of 80 to 500 VDC is applied within 1 to 5 minutes with 5 m of a wire sample of 6 m or more immersed in water for 1 hour or more, and the insulation resistance R (Ω) between the conductor and water is measured. Then, the unit is converted to (MΩ · km) by the calculation formula of R / 1000000/200. This measurement is performed at 20 ° C. and 90 ° C. In the case of 20 ° C., the insulation resistance R is required to be 11.4 MΩ · km or more, and in the case of 90 ° C., the insulation resistance R is required to be 0.114 MΩ · km or more.

(Flame retardancy test)
According to IEC 603322-1 vertical single-line combustion test (JIS C 3665-1). Specifically, the insulated wire is held vertically by the support material (upper support material), and the inner flame part by the Bunsen burner is set at a 45 ° angle for a predetermined time (time shown in JIS C 3665-1. Although it varies depending on the diameter, since it is 25 mm or less in this experiment, 60 seconds) After the flame contact, the burner is removed, the flame is turned off, and the degree of combustion of the sample is examined. A case where the distance between the lower end of the upper support and the carbonization start point is 50 mm or more is considered acceptable. Furthermore, when combustion spreads below 540 mm from the lower end of the upper support material, it was determined as rejected. In the table, “A” indicates pass and “C” indicates failure.

(Measurement of wear resistance)
EN50305-2002: 5.2 Based on Abrasion resistance. Diameter 0. Using a blade of 45 mmφ spring steel wire (piano wire), pressing the blade against an insulated wire with a load of 9 N (20 ° C.) and moving it by 10 to 20 mm is repeated at 50 to 60 cycles per minute. The number of wear until the blade contacts the conductor due to wear of the insulation coating is shown in the table. A wear frequency of 150 times or more is required.

(Oil resistance test)
The produced insulated wire was immersed in oil resistance test oil IRM902 in accordance with EN60881-1-3, heated in a constant temperature bath at 100 ° C. for 72 hours, and then allowed to stand at room temperature for about 16 hours. Thereafter, a tensile test was carried out, and the change in the value after oil immersion heating relative to the initial value was evaluated. The change in tensile strength was accepted within ± 30% of the initial value, and rejected when exceeding ± 30%. The change in tensile elongation was accepted within ± 30% of the initial value, and rejected when it exceeded ± 30%. In the table, “A” indicates pass and “C” indicates failure.

(Cold resistance test)
The produced electric wire was subjected to a low-temperature bending test at −40 ° C. according to EN60881-1-4 8.1. As a method, after putting a wire sample in a low temperature bath at −40 ° C. for 4 hours, the wire was placed on a metal mandrel having a diameter four times the insulation outer diameter of the wire while being kept at −40 ° C. in the low temperature bath. Wound around. And the thing which the crack generate | occur | produced at the time of bending was made disqualified, and the thing in which the crack did not generate | occur | produced was made acceptable. In the table, “A” indicates pass and “C” indicates failure.

(Combustion gas toxicity test)
About the insulation coating of the insulated wire produced as described above, a combustion gas toxicity test was performed as follows in accordance with EN50305 9.2, and a toxicity index was calculated. That is, for Experiments 1 to 20 and Experiments 27 to 40, sheets having a thickness of 1 mm prepared from the resin compositions for forming an insulating coating shown in Tables 1 to 4 and Tables 6 to 8, and for Experiments 21 to 26, A 1 mm thick sheet obtained by laminating a 0.08 mm thick layer composed of the inner layer preparing resin composition shown in FIG. 5 and a 0.92 mm thick layer composed of the outer layer preparing resin composition was cut into 5 mm squares, After being stored for 48 hours in a room at 23 ° C. and 50% relative humidity, it was decomposed in an oven at 800 ° C. for 20 minutes. The toxicity index (ITC) was calculated from the generation amounts of hydrogen cyanide, carbon monoxide, carbon dioxide, nitrogen oxides, and sulfur dioxide and the weighting of toxicity specified for each. An ITC of 6.0 or less was accepted.

From the results shown in the above table, EVA is 10% by mass or more and 60% by mass or less with respect to 100 parts by mass of polyolefin resin (polyethylene + EVA + maleic anhydride-modified ethylene α-olefin copolymer), and the melting point by DSC method is 60%. 5 mass% or more and 30 mass% or less of maleic anhydride-modified ethylene α-olefin copolymer having a temperature of ≦ ° C. or less, 100 to 250 parts by mass or less of a flame retardant (metal hydroxide), and viscosity at 25 ° C. Containing 1 part by mass or more and 20 parts by mass or less of silicone oil having a viscosity of 3000 mPa · s or less, and the base polymer has a melting point of 120 ° C. or more and 130 ° C. or less and a density of 0.925 or more and 0.945 or less. Insulation coating (or non-halogen flame retardant resin composition of Experiments 1 to 26 using polyethylene 2 or polyethylene 3 (or When the outer layer of the insulation coating is formed, tensile strength, tensile elongation, insulation resistance, and wear resistance that meet recent requirements (EN standards, etc.) have been obtained. Flame resistance test, oil resistance test, cold resistance test Has also been shown to pass.

Above all, in Experiments 17 and 18 in which spherical silica is added in an amount of less than 35 parts by mass with respect to 100 parts by mass of the polyolefin resin, the wear resistance is further improved.

From the results of Experiments 1 to 8, the silicone oil having a viscosity at 25 ° C. of 3000 mPa · s or less is modified with an alkyl group, an ester group, a vinyl group, a carboxyl group, an epoxy group, a hydroxyalkyl group, or an amino group. It has been shown that any type of silicone oil can be used and that the above effects can be achieved.

On the other hand, in Experiment 27 using a polyethylene 1 having a melting point of less than 120 ° C. and a density of less than 0.925 as the base polymer, the wear resistance is insufficient and the recent request is not satisfied. In Experiment 28 using polyethylene 4 having a melting point exceeding 130 ° C. and a density exceeding 0.945 as the base polymer, the cold resistance is insufficient.

In Experiment 29 where the amount of EVA is less than 10 parts by mass with respect to 100 parts by mass of the polyolefin resin, the cold resistance is insufficient. On the other hand, in Experiment 30 in which the amount of EVA exceeds 60 parts by mass with respect to 100 parts by mass of the polyolefin resin, the wear resistance is insufficient. This result shows that the amount of EVA should be 10% by mass or more and 60% by mass or less with respect to 100 parts by mass of the polyolefin resin in order to satisfy both wear resistance and cold resistance.

In Experiment 31 where the amount of the maleic anhydride-modified ethylene α-olefin copolymer is less than 5 parts by mass with respect to 100 parts by mass of the polyolefin resin, cold resistance is insufficient. On the other hand, in Experiment 32 in which the amount of the maleic anhydride-modified ethylene α-olefin copolymer exceeds 30 parts by mass with respect to 100 parts by mass of the polyolefin resin, the wear resistance and tensile strength are insufficient. As a result, in order to satisfy both the wear resistance, the tensile strength and the cold resistance, the amount of the maleic anhydride-modified ethylene α-olefin copolymer is 5% by mass or more and 30% by mass with respect to 100 parts by mass of the polyolefin resin. The following should be indicated.

Experiment 33 is a case where Tafmer MA8510 having a melting point exceeding 60 ° C. was used as the maleic anhydride-modified ethylene α-olefin copolymer, and the cold resistance was insufficient. This result indicates that a maleic anhydride-modified ethylene α-olefin copolymer having a melting point of 60 ° C. or lower should be used in order to obtain cold resistance satisfying recent requirements.

In Experiment 34 in which the amount of metal hydroxide is less than 100 parts by mass with respect to 100 parts by mass of the polyolefin resin, the flame retardancy does not meet the standard. On the other hand, in Experiment 35 in which the amount of metal hydroxide exceeds 250 parts by mass with respect to 100 parts by mass of the polyolefin resin, the tensile strength and cold resistance are insufficient. This result indicates that the amount of the metal hydroxide should be 100 parts by mass or more and 250 parts by mass or less with respect to 100 parts by mass of the polyolefin resin in order to satisfy both flame retardancy, tensile strength and cold resistance. ing.

Experiment 36 is a case where the content of spherical silica is 35 parts by mass or more with respect to 100 parts by mass of the polyolefin resin, and in this case, the cold resistance is insufficient. This result indicates that the content of spherical silica should be less than 35 parts by mass in order not to lower the cold resistance. Experiment 37 is a case where chain silica is used instead of spherical silica. In this case, even if the content is 30 parts by mass, cold resistance is insufficient. This result indicates that spherical silica should be used instead of chain silica in order not to reduce cold resistance.

Experiment 38 is a case where the amount of silicone oil exceeds 20 parts by mass with respect to 100 parts by mass of the polyolefin resin, and the abrasion resistance is insufficient. On the other hand, Experiment 39 is a case where silicone oil is not added (that is, the amount of silicone oil is less than 1 part by mass with respect to 100 parts by mass of polyolefin resin), and the flame retardancy is insufficient. This result indicates that the amount of silicone oil should be 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the polyolefin resin in order to satisfy both flame retardancy and wear resistance.

Experiment 40 is a case where a silicone oil having a viscosity at 25 ° C. exceeding 3000 mPa · s is used. In this case, flame retardancy and cold resistance are insufficient. This result shows that a silicone oil having a viscosity at 25 ° C. of 3000 mPa · s or less should be used.

In the experiments 21 to 25 having the inner layer, the insulation resistance was greatly improved and the wear resistance was also improved as compared with the case without the inner layer. From this result, it is considered that by providing the inner layer, the outer layer can be thinned and the insulating coating can be reduced in weight.

On the other hand, when the inner layer is not provided, the toxicity index (ITC) indicating the toxicity of the combustion gas generated when the insulating coating is burned is 6.0 or less. However, in Experiment 21 having the inner layer, the toxicity index (ITC) ) Exceeds 6.0, and it has been shown that the formation of an inner layer may increase the toxicity index (ITC). However, in Experiments 23 to 24 using a resin composition containing 5 to 200 parts by mass of aluminum silicate with respect to 100 parts by mass of polyethylene as a material for forming the inner layer, the toxicity index (ITC) was 6 It is shown that the toxicity of the combustion gas can be suppressed by blending a predetermined amount of aluminum silicate.

In Experiment 22 in which the content of aluminum silicate is less than 5 parts by mass with respect to 100 parts by mass of polyethylene, the toxicity index (ITC) exceeds 6.0, and the suppression of the toxicity of the combustion gas is insufficient. In Experiment 25 in which the content of aluminum silicate exceeds 200 parts by mass with respect to 100 parts by mass of polyethylene, although the toxicity index (ITC) is sufficiently reduced, the tensile strength and the tensile elongation are reduced. In Experiment 26 using magnesium hydroxide instead of aluminum silicate, the effect of suppressing the toxicity index (ITC) cannot be obtained. Furthermore, the insulation resistance is low, and the effect of improving the insulation resistance by providing the inner layer is not obtained. From the above results, in order to suppress the toxicity index (ITC), as a material for forming the inner layer, a resin composition containing 5 parts by mass or more and 200 parts by mass or less of aluminum silicate with respect to 100 parts by mass of polyethylene. It has been shown to be preferred.

1 Conductor 2 Inner layer 3 Outer layer 4 Insulated wire

Claims

100 parts by mass or more and 250 parts by mass or less of metal hydroxide, and 1 part by mass or more and 20 parts by mass or less of silicone oil having a viscosity at 25 ° C. of 3000 mPa · s or less with respect to 100 parts by mass of polyolefin resin. ,
The polyolefin resin is
30 mass% or more and 85 mass% or less of polyethylene whose melting point (Tm) by DSC method is 120 ° C. or more and 130 ° C. or less and whose density is 0.925 or more and 0.945 or less,
An ethylene-vinyl acetate copolymer of 10% by mass to 60% by mass, and a maleic anhydride-modified ethylene α-olefin copolymer having a melting point by DSC of 60 ° C. or less of 5% by mass to 30% by mass Non-halogen flame retardant resin composition to be contained.
The non-halogen flame retardant resin composition according to claim 1, wherein the silicone oil is a silicone oil modified with an alkyl group, an ester group, a vinyl group, a carboxyl group, an epoxy group, a hydroxyalkyl group or an amino group.
Furthermore, the non-halogen flame-retardant resin composition according to claim 1 or 2, further comprising 1 part by mass or more and less than 35 parts by mass of silica whose primary particles are spherical with respect to 100 parts by mass of the polyolefin resin.
A conductor and an insulating coating covering the conductor;
A non-halogen flame-retardant insulated electric wire comprising the cross-linked product of the non-halogen flame-retardant resin composition according to any one of claims 1 to 3, wherein the insulating coating.
With conductor and insulation coating,
The insulating coating has an inner layer covering the conductor and an outer layer covering the inner layer;
The inner layer is made of polyethylene or a composition mainly composed of polyethylene,
The non-halogen flame-retardant insulated electric wire which the said outer layer consists of a crosslinked body of the non-halogen flame-retardant resin composition of any one of Claim 1 thru | or 3.
The said inner layer consists of a crosslinked body of the non-halogen flame-retardant resin composition according to claim 5, wherein the inner layer is made of a resin composition containing 5 parts by mass or more and 200 parts by mass or less of aluminum silicate with respect to 100 parts by mass of polyethylene. Non-halogen flame retardant insulated wire.