JP2010144088A - Polyolefin composition and electrical wire and cable obtained by using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyolefin composition which does not generate halogen gas when burned but has excellent flame reterdancy and cold resistance and to provide an electrical wire and a cable each of which is obtained by using the polyolefin composition. <P>SOLUTION: The polyolefin composition contains: (A) 60-90 parts mass ethylene-propylene copolymer; (B) 10-40 parts mass (on condition that (A)+(B)=100 parts mass) one or more polymers selected from the group consisting of polyolefins, polydiolefins and ethylene copolymers other than the ethylene-propylene copolymer; (C) 30-50 parts mass metal hydrate; and (D) 3-10 parts mass phosphorus-based flame reterdant expressed in terms of the phosphorus element content on the basis of 100 parts mass ((A)+(B)). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a polyolefin-based composition that does not generate a halogen-based gas during combustion and has excellent flame retardancy and low-temperature characteristics, and an electric wire and cable using the same.

  The coating materials for electric wires and cables used in electrical and electronic equipment, etc., are mainly composed of an olefin-based composition containing a halogen-containing resin or a halogen-based flame retardant containing bromine or chlorine atoms in the molecule. Materials are often used. However, these halogen-based materials generate a large amount of smoke during combustion, and have problems such as corrosiveness to equipment and harmfulness to human bodies. Particularly recently, it has been strongly demanded not to generate such a halogen-based gas from the viewpoint of safety. In view of the above, metal hydrate flame retardants with very little fuming and toxic properties have attracted attention. However, in order to impart a high degree of flame retardancy, it is necessary to add a large amount of metal hydrate, thereby causing a problem that cold resistance is greatly reduced.

  Patent Document 1 discloses a halogen-free composition in which an organic peroxide crosslinking agent and a metal hydrate are added to a composition comprising EVA (ethylene-vinyl acetate copolymer) and EPDM (ethylene-propylene-diene copolymer). Although the flame retardancy and cold resistance are improved by adding triallyl isocyanate and N, N′-m-phenylenebismaleimide to the product, further cold resistance may be desired.

On the other hand, technologies that use silicone rubber or butadiene rubber have been proposed to maintain low-temperature characteristics, but silicone rubber has low tear strength and has the problem of contact failure due to volatilization of low molecular weight components. Not suitable. Further, butadiene rubber has low heat resistance, weather resistance, and ozone resistance, and it is not suitable as a wire coating material to be used in excess of 40% by mass as a polymer.
JP 2003-192865 A

  An object of the present invention is to provide a polyolefin-based composition that does not generate a halogen-based gas during combustion and has excellent flame retardancy and cold resistance, and an electric wire and a cable using the same.

  As a result of diligent research to solve the above problems, the present inventors have selected an ethylene / propylene copolymer selected from the group consisting of polyolefins, polydiolefins, and ethylene copolymers other than ethylene / propylene copolymers. It has been found that the above problems can be solved by combining two or more polymers in a specific ratio and adopting a metal hydrate and a phosphorus-based flame retardant as the flame retardant, thereby completing the present invention. It was.

That is, the present invention is as follows.
(1) One or more heavy selected from the group consisting of (A) 60-90 parts by mass of an ethylene / propylene copolymer, (B) polyolefin, polydiolefin, and ethylene copolymer other than ethylene / propylene copolymer The coalescence is 10-40 parts by mass (however, (A) + (B) = 100 parts by mass), (C) 30-50 parts by mass of metal hydrate and (D) phosphorus-based flame retardant converted to phosphorus element content And 3 to 10 parts by mass of a polyolefin-based composition.
(2) The polyolefin composition as described in (1), wherein the component (B) is butadiene rubber.
(3) The polyolefin composition as described in (1), wherein the component (B) is an ethylene / vinyl acetate copolymer.
(4) The polyolefin composition according to any one of (1) to (3), wherein the component (C) is magnesium hydroxide and / or aluminum hydroxide.
(5) An electric wire or cable obtained by coating the polyolefin-based composition according to any one of (1) to (4) as an insulating coating layer or a sheath coating layer.
(6) The electric wire or cable according to (5), wherein the insulating coating layer or the sheath coating layer is crosslinked.

The polyolefin-based composition of the present invention is an environmentally friendly non-halogen material, and can satisfy excellent flame retardancy and low-temperature characteristics even when metal hydrate and red phosphorus are used as flame retardants. Therefore, it is suitable as a coating material for electric wires and cables that require flame resistance, cold resistance, heat aging characteristics, and oil resistance.
Furthermore, by using this, it is possible to supply electric wires and cables excellent in the balance of flame retardancy, cold resistance, heat aging characteristics, and oil resistance.

  Hereinafter, the polyolefin-based composition of the present invention will be described in detail.

  The ethylene / propylene copolymer (A) which is the main component of the polyolefin-based composition of the present invention is an EPM which is a copolymer of ethylene and propylene and a terpolymer of ethylene, propylene and a non-conjugated diene. EPDM is exemplified, and examples of the non-conjugated diene include 1,4-hexadiene, ethylidene norbornene, vinyl norbornene, and dicyclopentadiene.

  (B) As polyolefin, thermoplastic resins, such as polyethylene and a polypropylene, are mentioned. Examples of the polydiolefin include synthetic rubber such as butadiene rubber and isoprene rubber, and natural rubber. Examples of ethylene copolymers other than ethylene / propylene copolymers include ethylene / vinyl acetate copolymers, ethylene / acrylic acid ester copolymers, ethylene / methacrylic acid ester copolymers, ethylene / acrylic acid copolymers, ethylene -A thermoplastic resin such as a methacrylic acid copolymer or an ethylene / butylene copolymer, a thermoplastic elastomer, or an ionomer. Further, polyolefins, polydiolefins, and ethylene copolymers other than ethylene / propylene copolymers that do not contain halogens modified with unsaturated carboxylic acids and / or derivatives thereof can also be used. Non-halogen-containing polyolefins, polydiolefins, ethylene copolymers other than ethylene / propylene copolymers, halogens modified with unsaturated carboxylic acids and / or derivatives thereof, polyolefins, polydiolefins, ethylene The ethylene copolymer other than the propylene copolymer may be used alone or in combination of two or more. The presence of the component (B) together with the component (A) does not impair the basic characteristics of the wire or cable coating material as compared with the component (A) alone, and maintains a low impact embrittlement temperature limit. , Oil resistance can be improved. The component (B) is 10 to 40 parts by mass ((A) + (B) = 100 parts by mass), preferably 70 to 80 parts by mass of the component (A) with respect to 60 to 90 parts by mass of the component (A). B) It is 20-30 mass parts of components. When there are too many (B) components, cold resistance may be impaired, and the heat aging characteristic and flexibility of (A) component may be impaired.

  (C) Examples of metal hydrates include hydroxyl groups or crystal water such as aluminum hydroxide, magnesium hydroxide, hydrated aluminum silicate, hydrated magnesium silicate, basic magnesium carbonate, orthosilicate aluminum, hydrotalcite, etc. A metal compound is mentioned, These may be individual or may combine 2 or more types.

  Among these metal hydrates, those having a crystal grain size in the range of 0.3 to 1.5 μm and having almost no aggregation are preferable, and the compatibility with the resin is improved. It may be surface-treated with a coupling agent or a fatty acid, or may be untreated. For example, “Hijilite” (manufactured by Showa Denko), “Kisuma” (manufactured by Kyowa Chemical Co., Ltd.) (both are trade names), and the like. The compounding quantity of a metal hydrate is 30-50 mass parts with respect to 100 mass parts of (A) + (B), Preferably it is 35-45 mass parts. If the amount is too small, the intended flame retardancy may not be obtained. If the amount is too large, the cold resistance may decrease.

  (D) Examples of the phosphorus flame retardant include red phosphorus, non-halogen phosphate ester, non-halogen condensed phosphate ester, reactive phosphate ester, and phosphate compound.

  The polyolefin-based composition of the present invention includes various commonly used resins and rubbers, and further additives (flame retardants, antioxidants, metal deactivators, ultraviolet absorbers, dispersants, crosslinking aids, A crosslinking agent, a reinforcing agent such as carbon or silica, a pigment, and the like) can be appropriately blended as necessary within the range not impairing the object of the present invention.

Furthermore, the composition of the present invention needs to be crosslinked after extrusion coating, and the polyolefin composition preferably contains a crosslinking agent.
As the crosslinking agent, an organic peroxide is preferable, and examples thereof include dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butyl peroxide) hexyne, and 1,3-bis- (t-butyl peroxide). Oxyisopropyl) benzene, 1,1, -di-t-butylperoxy-cyclohexane and the like. The blending amount is suitably 2 to 5 parts by mass with respect to 100 parts by mass of the base resin.
For the crosslinking treatment after extrusion coating, a steam crosslinking method, a molten salt crosslinking method, an electron beam irradiation crosslinking method, or a chemical crosslinking method can be used, but it is not particularly limited.

Electric wires and cables obtained by coating and coating the polyolefin composition of the present invention are excellent in terms of heat resistance because the composition of the coating layer is crosslinked. In general, the coating layer is crosslinked by extruding the polyolefin composition of the present invention on the outside of the conductor, followed by heating at 160 to 200 ° C. for crosslinking.
The electric wire of this invention should just use the said polyolefin-type composition for a coating layer, and a coating layer may be an insulating layer or a sheath layer. By using the polyolefin compound, the electric wire / cable is excellent in flame retardancy and cold resistance and does not generate a halogen-based gas during combustion.
Although it does not specifically limit about a cable, What is necessary is just to use the said several electric wire, An example was shown in FIG. FIG. 1 is an explanatory view showing an embodiment of an insulated cable in a sectional view. The cable of FIG. 1 is provided with a separator 2 and an insulator 3 on the outer periphery of a conductor 1. A plurality of these are twisted and the sheath 4 is collectively covered with this. In this example, the wires are twisted together, but an intervening layer may be provided between the wires without twisting the wires as necessary. The separator is used for improving the lead-out property, and usually paper or PET (polyethylene terephthalate) tape is used, but it is not used unless particularly required.

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

"Production of sheet"
Each component shown in Table 1 was prepared by kneading for about 10 to 20 minutes using a 1.7 L Banbury at 100 to 180 ° C and an 8-inch roll at 50 to 80 ° C. The obtained polyolefin-based composition was molded into a sheet and then subjected to a cross-linking treatment by pressing at 160 ° C. for 30 minutes to prepare test sheets for the following various tests.
In Table 1, EPDM represents an ethylene / propylene / diene copolymer, BR represents a butadiene rubber, EVA represents an ethylene / vinyl acetate copolymer, and LDPE represents a low density polyethylene.

"Production of electric wire"
To conduct a flame retardant test, a copper conductor obtained by twisting seven copper strands having a nominal cross-sectional area of 5 mm ² was coated with the polyolefin-based composition, and pressed using a mold at 160 ° C. for 30 minutes to obtain a wire sample. Was made.

1) Impact embrittlement limit temperature The impact embrittlement limit temperature was measured using a test sheet having a thickness of 2 mm in accordance with JIS K 6261 (vulcanized rubber and thermoplastic rubber—how to obtain low temperature characteristics). An impact embrittlement limit temperature of −65 ° C. or less was determined to be acceptable (“◯” and “x” failed).

2) Flame retardance Using a wire sample with an outer diameter of 13 mm, 28. JIS C 3005 (Rubber / plastic insulated wire test method). The test was carried out in accordance with an inclination test for flame retardancy. After removing the flame, the case where the flame naturally disappeared within 30 seconds was regarded as pass (circled, x is unacceptable).

3) Thermal aging characteristics (elongation residual rate)
Using a test sheet having a thickness of 2 mm, the sample was heated at 100 ° C. for 96 hours in accordance with A-2 method of JIS K 6257 (vulcanized rubber and thermoplastic rubber—how to obtain heat aging characteristics), and the tensile elongation was The residual rate was calculated. 80% or more was determined to be acceptable (“◯” and “x” is unacceptable).

4) Oil resistance Using a test sheet having a thickness of 2 mm, based on JIS C 3005, the residual ratio of the tensile strength was calculated by immersion test at 70 ° C. for 4 hours using IRM902 test oil. 50% or more was determined to be acceptable (circled. X was unacceptable).

About each produced sheet | seat and electric wire, impact embrittlement limit temperature, a flame retardance, a heat aging characteristic, and oil resistance were evaluated based on the said method. The results are shown in Table 1 together with the composition.

  As shown in Table 1, the resin compositions of Examples 1 to 6 of the present invention had an impact embrittlement limit temperature of −65 ° C. or lower while passing the gradient combustion test, and further had a residual tensile elongation after heat aging. It can be seen that the rate is 80% or more, and the tensile strength after immersion in oil resistance is 50% or more. In contrast, Comparative Example 1 uses only EPDM as the polymer and has a large amount of metal hydrate, so that the impact embrittlement limit temperature is considerably higher than -65 ° C. In Comparative Example 2, only EPDM is used as the polymer, and since the metal hydrate is too small, the tensile strength after the oil resistance test is low. Moreover, since the comparative examples 3 and 4 do not use red phosphorus, only the metal hydrate fails the 60-degree inclined flame retardant. Moreover, since the comparative example 5 has too much metal hydrate, the impact embrittlement limit temperature is higher than -65 degreeC. Moreover, since the comparative example 6 uses 50 mass parts or more of butadiene rubbers, although the impact embrittlement limit temperature is lower than -65 degreeC, it turns out that a heat aging characteristic is bad.

It is a schematic sectional drawing which shows one embodiment of the cable using the composition of this invention.

Explanation of symbols

1 Conductor 2 Separator 3 Insulator 4 Sheath Layer

Claims (6)

  There are 10 or more polymers selected from the group consisting of (A) ethylene / propylene copolymer 60 to 90 parts by mass, (B) polyolefin, polydiolefin, and ethylene copolymer other than ethylene / propylene copolymer. To 40 parts by mass [(A) + (B) = 100 parts by mass], (C) 30-50 parts by mass of metal hydrate and (D) phosphorus flame retardant are converted to phosphorus element content. 3 to 10 parts by mass of a polyolefin-based composition.   The polyolefin composition according to claim 1, wherein the component (B) is a butadiene rubber.   The polyolefin-based composition according to claim 1, wherein the component (B) is an ethylene / vinyl acetate copolymer.   (C) A component is magnesium hydroxide and / or aluminum hydroxide, The polyolefin-type composition of any one of Claims 1-3 characterized by the above-mentioned.   An electric wire or cable comprising the polyolefin-based composition according to any one of claims 1 to 4 coated as an insulating coating layer or a sheath coating layer.   The electric wire or cable according to claim 5, wherein the insulating coating layer or the sheath coating layer is subjected to a crosslinking treatment.

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