JP2011049116A - Fire-resistant composition for electric cable coating, and electric cable - Google Patents

Abstract

The present invention provides a flame-retardant composition for covering electric wires and cables that is halogen-free and has both excellent flame resistance and water / moisture resistance, and an electric wire / cable using such a composition.
A non-halogen flame retardant composition comprising (A) a component having a specific gravity of 1.26 or more obtained by blending a metal hydroxide as a flame retardant with an olefin polymer, and (B) a silane crosslinkable. For coating electric wires and cables, which are mixed with a component containing an olefin polymer at a mass ratio of 50:50 to 95: 5, and have a water absorption of 7% or less after being immersed in hot water at 90 ° C. for 80 days. A flame retardant composition, and an electric wire / cable having a coating made of such a composition.
[Selection figure] None

Description

  The present invention relates to a flame-retardant resin composition that is halogen-free and excellent in flame retardancy and water / humidity resistance, and to an electric wire / cable using the same.

  In recent years, in the electric wire / cable field, in order to reduce the burden on the environment, instead of a composition containing polyvinyl chloride (PVC) or a halogen-based flame retardant that generates harmful gases such as hydrogen halide during incineration. In recent years, electric wires and cables using a halogen-free composition made of flame retardant by adding a large amount of metal hydroxide such as aluminum hydroxide or magnesium hydroxide to polyolefin have been used.

  However, such a halogen-free flame retardant composition has a high water absorption and hygroscopicity because a large amount of metal hydroxide is added, and once the water is absorbed or absorbed, the volume resistivity decreases, There was a problem that the function as an insulator could not be maintained.

  Conventionally, various methods for improving the properties of this type of polyolefin-based flame retardant composition have been proposed, for example, silane crosslinking to improve heat resistance and mechanical properties (see, for example, Patent Document 1). However, no effective measures have yet been found for water absorption and hygroscopicity.

JP 2000-212291 A

  The present invention has been made in order to solve such problems of the prior art, and is a halogen-free flame retardant composition that has excellent flame retardancy and water / moisture resistance. An object is to provide a flammable composition and an electric wire / cable using such a flame retardant composition.

In order to solve the above object, the invention described in claim 1 is a non-halogen flame retardant composition comprising a specific gravity of 1. (A) an olefin polymer and a metal hydroxide as a flame retardant. 26 or more components and (B) a component containing a silane crosslinkable olefin polymer are mixed at a mass ratio of 50:50 to 95: 5, and after being immersed in hot water at 90 ° C. for 80 days. A flame retardant composition for covering electric wires and cables, having a water absorption of 7% or less.
It is.

  The invention described in claim 2 is the flame retardant composition for covering electric wires and cables according to claim 1, wherein the water absorption is 5% or less. It is a thing.

  The invention described in claim 3 is the flame retardant composition for covering an electric wire / cable according to claim 1 or 2, wherein the mixing ratio of the component (A) and the component (B) is 50:50 by mass ratio. It is the flame-retardant composition for electric wire and cable coating | cover characterized by being -90: 10.

  The invention described in claim 4 is the flame retardant composition for electric wire / cable coating according to any one of claims 1 to 3, wherein the olefin polymer of the component (A) and the component (B) is Polyethylene, polypropylene, polyisobutylene, ethylene / propylene copolymer, ethylene / propylene / diene copolymer, ethylene / acrylic acid copolymer, ethylene / ethyl acrylate copolymer, ethylene / methyl acrylate copolymer, Flame retardant for electric wire / cable coating, characterized by being at least one selected from the group consisting of ethylene / ethyl methacrylate copolymer, ethylene / ethyl methacrylate copolymer and ethylene / vinyl acetate copolymer It is a composition.

  The invention described in claim 5 is the flame retardant composition for covering an electric wire or cable according to any one of claims 1 to 4, wherein the metal hydroxide of the component (A) is magnesium hydroxide, It is a flame retardant composition for covering electric wires and cables, which is at least one selected from the group consisting of aluminum hydroxide, zirconium hydroxide, calcium hydroxide and barium hydroxide.

  The invention described in claim 6 is the flame retardant composition for covering an electric wire / cable according to any one of claims 1 to 5, wherein the silane-crosslinkable olefin-based polymer as the component (B) has a low content. A flame retardant composition for covering electric wires and cables, which is obtained by grafting vinyltrimethoxysilane onto high density polyethylene.

The invention described in claim 7 is the flame specific composition for covering electric wires and cables according to any one of claims 1 to 6, wherein the volume resistivity after being immersed in hot water at 90 ° C. for 80 days. Is a flame retardant composition for covering an electric wire / cable, characterized by being 1.0 × 10 ¹¹ Ω · cm or more.

  The invention described in claim 8 is an electric wire / cable having a coating made of the flame retardant composition for electric wire / cable coating according to any one of claims 1 to 7.

  The flame retardant composition for covering an electric wire / cable of the present invention is halogen-free and can have both excellent flame retardancy and water / moisture resistance.

  Moreover, since the electric wire / cable of the present invention is provided with the coating having the above-described characteristics, it can be an electric wire / cable having both excellent flame-free flame resistance and water / moisture resistance.

It is sectional drawing which shows an example of the electric wire and cable of this invention.

  Embodiments of the present invention will be described below.

  First, the flame retardant composition for covering electric wires and cables of the present invention will be described.

  Examples of the olefin polymer of component (A) used in the flame retardant composition for covering electric wires and cables of the present invention include ethylene / propylene copolymer (EPM), ethylene / propylene / diene copolymer (EPDM) and the like. Ethylene propylene rubber, low density polyethylene (LDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), very low density polyethylene (VLDPE), linear low density polyethylene (LLDPE) and other polyethylene, polypropylene (PP ), Ethylene / acrylic acid copolymer, ethylene / ethyl acrylate copolymer (EEA), ethylene / methyl acrylate copolymer (EMA), ethylene / ethyl methacrylate copolymer, ethylene / vinyl acetate copolymer (EVA), polyisobutylene and the like are exemplified. Moreover, what copolymerized alpha-olefin, cyclic olefins, etc., such as propylene, butene, pentene, hexene, and octene, can be used for the metallocene catalyst. These may be used individually by 1 type and may be used in combination of 2 or more type. As the olefin polymer of the component (A), an ethylene / vinyl acetate copolymer and low density polyethylene (LDPE) are preferable, and other olefin polymers are preferably used as their combined components. The component (A) olefin polymer is more preferably an ethylene / vinyl acetate copolymer.

  In addition, the metal hydroxide blended with the component (A) as a flame retardant releases water when exposed to high temperatures, and exhibits a flame retardant effect by suppressing the temperature rise with the heat of vaporization at that time. Yes, magnesium hydroxide, aluminum hydroxide, zirconium hydroxide, calcium hydroxide, barium hydroxide, etc. are exemplified. These metal hydroxides may be subjected to surface treatment with higher fatty acids such as stearic acid, silane coupling agents, molybdates and the like. By using such a surface-treated metal hydroxide, the dispersibility when kneading with the polymer component can be enhanced. A metal hydroxide may be used individually by 1 type, and may be used in combination of 2 or more type.

  The compounding amount of the metal hydroxide is preferably in the range of 30 to 200 parts by mass, more preferably in the range of 50 to 150 parts by mass with respect to 100 parts by mass of the olefin polymer. If it is less than 30 parts by mass, the flame retardancy is lowered, and if it exceeds 200 parts by mass, mechanical properties and flexibility are lowered.

  In the component (A), other non-halogen flame retardants other than the metal hydroxides described above can also be blended within a range that does not impair the effects of the present invention. Examples of such non-halogen flame retardants include guanidine-based and melamine-based nitrogen-based flame retardants, phosphorus-based flame retardants such as ammonium phosphate and red phosphorus, phosphorus-nitrogen-based flame retardants, and boric acid compounds such as zinc borate. And calcium carbonate.

  The component (A) further includes an antioxidant, an ultraviolet absorber, a heat aging inhibitor, a filler, a processing aid, a lubricant, a colorant, etc., as necessary, as long as the effects of the present invention are not impaired. Additives can be blended.

  In addition, from the viewpoint of balancing flame resistance and water / humidity resistance, the component (A) preferably has a specific gravity of 1.26 or more, more preferably 1.3 to 1.4.

  The component (B) silane-crosslinkable olefin polymer used in the flame retardant composition for covering electric wires and cables of the present invention is obtained by grafting a silane compound to an olefin polymer. This silane crosslinkable olefin polymer is obtained by adding a silane compound together with a radical generator to the olefin polymer, kneading with an extruder, a kneader, etc., and grafting the silane compound onto the polymer chain of the olefin polymer. It is done.

  Examples of the olefin polymer include those similar to the olefin polymer of the component (A) described above, among which low density ethylene, very low density polyethylene (VLDPE), and linear low density polyethylene (LLDPE). Low density polyethylene and linear low density polyethylene (LLDPE) are more preferable. As the silane compound, those generally known as silane coupling agents such as vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldiethoxysilane, vinylphenyldimethoxysilane, vinyltributoxysilane and the like are used. These silane compounds may be used individually by 1 type, and may be used in combination of 2 or more type. Furthermore, as the radical generator, dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di- (tert-butylperoxy) hexane, 2,5-dimethyl-2,5- Di- (tert-butylperoxy) hexyne-3, 1,3-bis (tert-butylperoxyisopropyl) benzene, 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane, n-butyl-4,4-bis (tert-butylperoxy) valerate, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, tert-butylperoxybenzoate, tert-butylperoxyisopropyl carbonate, diacetyl peroxide, Lauroyl peroxide, ter - and butyl cumyl peroxide and the like. The silane compound is usually added in an amount of 0.5 to 5 parts by mass with respect to 100 parts by mass of the olefin polymer. Further, the radical generator is usually added in an amount of 0.02 to 1 part by mass with respect to 100 parts by mass of the olefin polymer.

  In the component (B), an olefin polymer other than the above-mentioned silane crosslinkable olefin polymer can be blended within a range that does not impair the effects of the present invention. Further, if necessary, additives such as an antioxidant, an ultraviolet absorber, a heat aging inhibitor, a filler, a processing aid, a lubricant, and a colorant may be blended within a range that does not impair the effects of the present invention. it can. The component (B) can further be blended with a catalyst for promoting cross-linking between molecules of the silane crosslinkable olefin polymer. Examples of such a catalyst include dibutyltin dilaurate, dibutyltin dimaleate, dibutyltin diacetate, dibutyltin methylcaptide, stannous octoate, and tetrabutene titanate. The crosslinking catalyst is usually blended in an amount of 0.01 to 0.2 parts by mass with respect to 100 parts by mass of the silane crosslinkable olefin polymer. In addition, a catalyst may be mix | blended with (A) component and may be mix | blended with both (A) and (B) component.

  The flame retardant composition for covering an electric wire / cable of the present invention is prepared by mixing each component blended with the component (A) and each component blended with the component (B) with a Banbury mixer, a tumbler, a pressure kneader, and a kneader, respectively. It can be easily produced by uniformly mixing using a normal kneader such as an extruder or mixing roller, and further mixing the mixture uniformly using a normal kneader.

  The mixing ratio of the component (A) and the component (B) is preferably 50:50 to 90:10 by mass ratio. When the proportion of the component (A) is less than the above range, the flame retardancy is lowered. Conversely, when the proportion of the component (A) is more than the above range, water resistance and moisture resistance cannot be sufficiently improved.

  In this invention, it is also possible to use a commercially available composition as (A) component and (B) component, respectively. As a commercial item of (A) component, EJ-C2102, EJ-C2104 (above, Showa Kasei Kogyo Co., Ltd. product name), QE1594, QE1597-1 (above, Apco Co., Ltd.), ANA9906P (Riken Technos Co., Ltd. trade name) ) And the like. Moreover, as a commercial item of (B) component, XLE815N, XCF710N, XCF730N (above, the Mitsubishi Chemical Corporation brand name), QS161Z, QS183NZ, QS672RZ (above, Apco company make) etc. are mentioned, for example.

  The flame retardant composition for covering an electric wire / cable of the present invention has excellent flame retardancy and has an excellent water absorption of 7% or less after being immersed in hot water at 90 ° C. for 80 days. Has water and moisture resistance. The water absorption after immersion in hot water at 90 ° C. for 80 days is preferably 5% or less.

The flame retardant composition for covering an electric wire / cable of the present invention preferably has a volume resistivity of 1.0 × 10 ¹¹ Ω · cm or more after being immersed in hot water at 90 ° C. for 80 days, More preferably, it is 1.0 × 10 ¹² Ω · cm or more.

  Furthermore, the flame retardant composition for covering electric wires and cables of the present invention preferably has an oxygen index measured by JIS K 6251 of 25 or more, more preferably 28 or more.

  The flame retardant composition for electric wire / cable coating of the present invention includes, for example, power cables, control cables, communication cables, signal cables, movement cables, ship cables, insulation materials for various electric wires and cables such as insulated wires, sheaths It can be used as a material or an intervening material. In particular, since the flame retardant composition for covering electric wires and cables of the present invention has excellent flame resistance and water / moisture resistance, it is in contact with water, such as electric wires for outdoor wiring, in a high humidity environment or directly. It is useful as an insulation material, sheath material, and interposition material for electric wires and cables used in such an environment.

  Next, the electric wire / cable of the present invention will be described.

  The electric wire / cable of the present invention is manufactured by winding the above-mentioned flame retardant composition for electric wire / cable coating directly or through other coatings on the outer periphery of the conductor, or by winding a tape-shaped one. Is done. The composition is silane crosslinked after coating or molding.

  FIG. 1 is a cross-sectional view showing an embodiment of the electric wire / cable of the present invention.

In FIG. 1, 1 shows a copper stranded wire conductor having a cross-sectional area of 2 mm ² , for example. On the copper stranded wire conductor 1, the above-described flame retardant composition for covering electric wires and cables is extrusion coated. For example, the insulator 2 having a thickness of 0.8 mm is formed.

  The insulated electric wire configured as described above has excellent halogen-free flame retardancy and excellent water resistance and moisture resistance.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples at all.

Examples 1 to 6, Comparative Examples 1 and 2
100 parts by mass of ethylene / vinyl acetate copolymer (trade name EV250 manufactured by Mitsui DuPont Polychemical Co., Ltd.), 100 parts by mass of magnesium hydroxide (trade name Mag Seeds S-4 manufactured by Kamishima Chemical Co., Ltd.), and antioxidant (Ciba Specialty) (Product name: Irganox 1010) 0.5 part by mass was uniformly kneaded using a pressure kneader to obtain component (A). Further, 100 parts by mass of low density polyethylene is blended with 2 parts by mass of vinyltrimethoxysilane and 0.1 part by mass of dicumyl peroxide, put into an extruder, heated and kneaded, and vinyltrimethoxysilane is added to low density polyethylene. Then, 0.05 parts by mass of dibutyltin dilaurate was added to the compound and uniformly kneaded using an extruder to obtain component (B).

  The obtained component (A) and component (B) were uniformly kneaded with a mixing roll at a blending ratio (mass ratio) shown in Table 1, and then extruded into a sheet shape.

  Subsequently, each said sheet | seat was immersed in 60 degreeC warm water for 24 hours, and the silane bridge | crosslinking was carried out, and the sheet | seat for a test was produced. In addition, the test sheet produced 2 types with thickness 2mm and thickness 3mm.

  About the obtained sheet | seat for a test, the water absorption rate, the volume resistivity (initial stage and after hot water immersion), and the oxygen index were measured by the method shown below. A test sheet having a thickness of 2 mm was used for measuring the water absorption rate and the volume resistivity, and a test sheet having a thickness of 3 mm was used for measuring the oxygen index.

[Water absorption rate]
The test sheet was immersed in hot water at 90 ° C. for 80 days, and then immediately measured by the Karl Fischer method.
[Volume resistivity (initial and after immersion in hot water)]
Measured based on JIS K 6723. The volume resistivity after the immersion was measured by immersing the test sheet in hot water at 90 ° C. for 80 days, sealing with aluminum foil, cooling to 23 ° C., and then measuring.
[Oxygen index]
It measured based on JISK7201-2.

  These results are shown in the lower column of Table 1.

As is apparent from Table 1, the flame retardant composition for covering electric wires and cables according to the examples has a water absorption rate of 7% or less after being immersed in hot water, and therefore after being immersed in hot water at 90 ° C. for 80 days. Also had a volume resistivity of 1.0 × 10 ¹¹ Ω · cm or more, and the insulating performance sufficiently functioning as an insulator was maintained. Moreover, the oxygen index was 25 or more, and the flame retardancy was good. In particular, in Examples 3 to 5 in which the mixing ratio of the component (A) and the component (B) was 70:30 to 80:20, both flame retardancy and water / moisture resistance were better. On the other hand, in Comparative Example 1 in which the silane crosslinkable olefin polymer was not blended, the volume resistivity was greatly reduced, and in Comparative Example 2 in which the silane crosslinkable olefin polymer was excessively blended, the oxygen index was low. Small and good flame retardancy could not be obtained.

  DESCRIPTION OF SYMBOLS 1 ... Copper twisted wire conductor, 2 ... Insulating layer.

Claims (8)

A non-halogen flame retardant composition comprising:
(A) A component having a specific gravity of 1.26 or more obtained by blending a metal hydroxide as a flame retardant into an olefin polymer, and (B) a component containing a silane crosslinkable olefin polymer, 50:50 to 95 A flame retardant composition for covering electric wires and cables, which is mixed at a mass ratio of 5 and has a water absorption of 7% or less after being immersed in hot water at 90 ° C. for 80 days.   The flame retardant composition for covering electric wires and cables according to claim 1, wherein the water absorption is 5% or less.   The flame retardant composition for covering electric wires and cables according to claim 1 or 2, wherein the mixing ratio of the component (A) and the component (B) is 50:50 to 90:10 in terms of mass ratio.   The olefin polymers of the component (A) and the component (B) are polyethylene, polypropylene, polyisobutylene, ethylene / acrylic acid copolymer, ethylene / ethyl acrylate copolymer, ethylene / methyl acrylate copolymer, 4. At least one selected from the group consisting of an ethylene / ethyl methacrylate copolymer, an ethylene / ethyl methacrylate copolymer, and an ethylene / vinyl acetate copolymer. The flame retardant composition for covering electric wires and cables according to item 1.   The metal hydroxide as the component (A) is at least one selected from the group consisting of magnesium hydroxide, aluminum hydroxide, zirconium hydroxide, calcium hydroxide, and barium hydroxide. The flame retardant composition for covering an electric wire / cable according to any one of 1 to 4.   The electric wire / cable according to any one of claims 1 to 5, wherein the silane-crosslinkable olefin polymer of the component (B) is obtained by grafting vinyltrimethoxysilane to low density polyethylene. Flame retardant composition for coating. The wire / cable coating according to any one of claims 1 to 6, wherein the volume resistivity after being immersed in hot water of 90 ° C for 80 days is 1.0 × 10 ¹¹ Ω · cm or more. Flame retardant composition.   An electric wire / cable having a coating made of the flame retardant composition for covering an electric wire / cable according to any one of claims 1 to 7.

Images