JP2007059336A - Flame-resistant wire/cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flame-resistant wire/cable having flame resistance equivalent to that of PVC, using a non-halogen flame-resistant coating material excelling in a mechanical characteristic and having high environmental protection. <P>SOLUTION: This flame-resistant wire/cable has, in the circumference of a conductor, a non-halogen flame-resistant coating containing, for instance, an ethylene-based polymer with an ethylene-vinyl acetate copolymer as the main constituent. In the flame-resistant wire/cable, the non-halogen flame-resistant coating has a flame-resistant layer, formed of a non-halogen flame-resistant composition containing 3-30 pts.wt. of thermally-expandable graphite with respect to 100 pts.wt. of ethylene-based polymer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a flame retardant electric wire / cable having high environmental conservation and coated with a non-halogen flame retardant material.

  Polyvinyl chloride (PVC) has relatively good insulation properties and is excellent in flame retardancy because it contains halogen (Cl) in the molecule. Furthermore, it has oil resistance, ozone resistance, chemical resistance, and water resistance. Etc., it is widely used as an insulator and sheath material for electric wires and cables.

  On the other hand, in recent years, as awareness of global environmental protection has increased, there has been an increasing movement to regulate the use of materials with a large environmental load, and the above-mentioned PVC is also harmful due to halogens in the event of a fire or incineration. The use of halogen gas and dioxin is being limited due to the generation of halogen gas and dioxin.

  For this reason, a highly environmentally friendly flame retardant material for covering wires and cables that replaces PVC, that is, a non-halogen flame retardant material that does not contain halogen and does not generate harmful substances such as halogen gas or dioxin during combustion. There is a strong demand.

  As such non-halogen flame retardant materials for covering electric wires and cables, flame retardant ethylene polymers, for example, flame retardant by adding a large amount of metal hydroxide such as magnesium hydroxide or aluminum hydroxide to polyethylene Is known (for example, see Patent Document 1).

However, in this composition, due to the addition of a large amount of metal hydroxide, the original excellent properties of the ethylene-based polymer, especially mechanical properties (for example, tensile strength, elongation, etc.) are impaired. There is a problem that the cable cannot have sufficient required characteristics.
JP 2000-11765 A

  As described above, there is a demand for a non-halogen non-halogen wire / cable flame retardant material that replaces PVC, but metals such as magnesium hydroxide and aluminum hydroxide have been added to conventional flammable ethylene polymers. The flame retardant added with a hydroxide has a problem that the mechanical properties are particularly deteriorated.

  The present invention has been made in order to solve such problems of the prior art, and has environmental protection using a non-halogen flame retardant coating material having flame resistance comparable to PVC and excellent mechanical properties. The purpose is to provide highly resistant flame retardant wires and cables.

  As a result of intensive studies to achieve the above object, the inventors of the present invention have a heat expansion property that greatly expands in the C-axis direction (a direction perpendicular to the cleavage plane of graphite) by rapid heating with respect to an ethylene-based polymer. By providing a coating with a flame retardant layer made of a non-halogen flame retardant composition containing a specific amount of graphite, non-halogen having flame retardant properties and mechanical properties comparable to electric wires and cables using conventional halogen-based materials The present inventors have found that a flame retardant electric wire / cable can be obtained and have completed the present invention.

  That is, the flame-retardant electric wire / cable of the invention according to claim 1 of the present application is a flame-retardant electric wire / cable having a non-halogen flame-retardant coating mainly composed of an ethylene-based polymer on the outer periphery of the conductor. The flammable coating is characterized by having a flame retardant layer composed of a non-halogen flame retardant composition containing 3 to 30 parts by weight of heat-expandable graphite with respect to 100 parts by weight of an ethylene-based polymer.

  According to a second aspect of the present invention, in the flame retardant electric wire / cable according to the first aspect, the non-halogen flame retardant coating is red with 3 to 30 parts by weight of heat-expandable graphite with respect to 100 parts by weight of the ethylene polymer. It has a flame retardant layer comprising a non-halogen flame retardant composition containing 3 to 30 parts by weight of a phosphorus flame retardant.

  The invention according to claim 3 is the flame retardant electric wire / cable according to claim 1 or 2, wherein the ethylene polymer is polyethylene, polypropylene, ethylene / ethyl acrylate copolymer, ethylene / vinyl acetate copolymer and ethylene. -It is at least 1 sort (s) chosen from the group which consists of a propylene copolymer, It is characterized by the above-mentioned.

  According to a fourth aspect of the present invention, in the flame retardant electric wire / cable according to the third aspect, the ethylene-based polymer contains an ethylene / vinyl acetate copolymer.

  The invention according to claim 5 is the flame retardant electric wire / cable according to any one of claims 1 to 4, wherein the non-halogen flame retardant coating comprises the flame retardant layer and a heat expansion property provided on an outer periphery thereof. And a surface protective layer substantially free of graphite.

  The invention according to claim 6 is the flame-retardant electric wire / cable according to claim 5, wherein the surface protective layer has a tensile strength of 10 MPa or more and an elongation of 350%.

  The invention according to claim 7 is the flame retardant electric wire / cable according to any one of claims 2 to 4, wherein the non-halogen flame retardant coating includes the flame retardant layer and a heat expansion property provided on an outer periphery thereof. And a surface protective layer substantially free of graphite and red phosphorus flame retardant.

  The invention according to claim 8 is the flame-retardant electric wire / cable according to claim 7, wherein the surface protective layer has a tensile strength of 10 MPa or more and an elongation of 350%.

  In addition, the said tensile strength and elongation are the values measured based on JISC3005.

  According to the flame retardant electric wire / cable of the present invention, the flame retardant electric wire / cable using the conventional halogen-based material can be provided with good flame retardancy and excellent in mechanical properties. .

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view showing an embodiment of the flame-retardant electric wire of the present invention, and FIG. 2 is a cross-sectional view showing an embodiment of the flame-retardant cable of the present invention.

  A flame retardant electric wire 10 shown in FIG. 1 has a configuration in which a flame retardant insulating layer 2 made of a non-halogen flame retardant composition is coated on a conductor 1 made of copper, aluminum or the like. In addition, the flame retardant cable 20 shown in FIG. 2 is provided with an insulating layer 2A made of a normal non-halogen insulating material such as polyethylene or cross-linked polyethylene on the conductor 1 made of copper, aluminum, or the like. The flame retardant sheath 3 made of a non-halogen flame retardant composition is coated.

  The non-halogen flame retardant composition constituting the flame retardant insulating layer 2 of the flame retardant electric wire 10 and the flame retardant sheath 3 of the flame retardant cable 20 contains 3 to 30 parts by weight of heat-expandable graphite with respect to 100 parts by weight of the ethylene polymer. Preferably, it further contains 3 to 30 parts by weight of a red phosphorus flame retardant.

  Examples of the ethylene-based polymer include polyethylene such as low density polyethylene (LDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), very low density polyethylene (VLDPE), linear low density polyethylene (LLDPE), and polypropylene ( PP), ethylene / ethyl acrylate copolymer (EEA), ethylene / methyl acrylate copolymer (EMA), ethylene / ethyl methacrylate copolymer, ethylene / vinyl acetate copolymer (EVA), ethylene / propylene Examples thereof include a copolymer (EP), an ethylene / propylene / diene copolymer (EPDM), and polyisobutylene. Moreover, what copolymerized alpha-olefin, cyclic olefins, etc., such as propylene, butene, pentene, hexene, and octene, can be used for the metallocene catalyst. These are used alone or in combination. In the present invention, among these, the use of at least one selected from the group consisting of polyethylene, polypropylene, ethylene / ethyl acrylate copolymer, ethylene / vinyl acetate copolymer and ethylene / propylene copolymer is particularly preferable. The use of an ethylene / vinyl acetate copolymer is preferable for obtaining good mechanical properties.

  Heat-expandable graphite is a black flake-like substance obtained by oxidizing flake graphite and has the property of expanding greatly in the C-axis direction (direction perpendicular to the cleavage plane of graphite) when rapidly heated. It is what you have. Specifically, for example, a frame cut GREP-EG (trade name, manufactured by Tosoh Corporation) that expands 100 to 300 times in the C-axis direction at 1000 ° C. is used.

  This heat-expandable graphite has a flame retarding effect when individual particles form porous carbides during expansion, and the carbides block oxygen intrusion and heat conduction. By using together with a flame retardant, each effect is synergistic and exhibits excellent flame retardant effect and fire spread prevention effect.

  Examples of the red phosphorus flame retardant used in combination include Nova Red 120, Nova Excel 140, Novaquel ST100, Novaquel FST100 (above, product name manufactured by Rin Chemical Industry Co., Ltd.), Hishiguard CP-A15, Hishiguard TP-10, Hishiguard Safe. PM-24, Hishiguard Safe PM-31 (trade name, manufactured by Nippon Kagaku Kogyo Co., Ltd.), Exolit RP 602, Exolit RP 605, Exolit RP 614 (trade name, manufactured by Clariant), etc. are used.

  As described above, these heat-expandable graphite and red phosphorus flame retardant are blended in an amount of 3 to 30 parts by weight with respect to 100 parts by weight of the ethylene polymer. If the blending amount is less than 3 parts by weight, self-extinguishing properties cannot be obtained. Conversely, if the blending amount exceeds 30 parts by weight, mechanical properties such as tensile strength and elongation decrease. A preferable blending amount of the heat-expandable graphite and the red phosphorus flame retardant is in the range of 5 to 15 parts by weight with respect to 100 parts by weight of the ethylene polymer.

  In addition, the non-halogen flame retardant composition constituting the flame retardant insulating layer 2 of the flame retardant wire 10 and the flame retardant sheath 3 of the flame retardant cable 20 may be oxidized within a range that does not impair the effects of the present invention, if necessary. Additives such as an inhibitor, an ultraviolet absorber, a heat aging inhibitor, a processing aid, a lubricant, and a stabilizer may be blended.

  Since the flame retardant electric wire 10 and the flame retardant cable 20 configured as described above do not contain halogen, no harmful substances such as halogen gas or dioxin are generated in the event of a fire or incineration. It has excellent flame retardancy comparable to that using halogen-based materials. In addition, it has sufficient characteristics required for electric wires and cables without deterioration of mechanical characteristics as in the case of using a flame retardant material by adding a conventional metal hydroxide.

  In the present invention, as shown in FIGS. 3 and 4, respectively, the flame retardant insulating layer 2 constituting the outermost layer of the flame retardant electric wire 10 shown in FIG. 1 or the outermost layer of the flame retardant cable 20 shown in FIG. On the surface of the flame retardant sheath 3 constituting the outer layer, the surface protective layer 4 is formed from heat-expandable graphite or a non-halogen composition substantially free of heat-expandable graphite and red phosphorus flame retardant. Also good. That is, the flame retardant wire 30 shown in FIG. 3 is an example in which the surface protective layer 4 is further provided on the flame retardant insulating layer 2 made of a non-halogen flame retardant composition in the flame retardant wire 10 shown in FIG. Moreover, the flame retardant cable 40 shown in FIG. 4 is an example in which the surface protective layer 4 is further provided on the flame retardant sheath 3 made of a non-halogen flame retardant composition in the flame retardant cable 20 shown in FIG.

  As the non-halogen composition for forming the surface protective layer 4, heat-expandable graphite or a material obtained by removing heat-expandable graphite and a red phosphorus flame retardant from the above-mentioned non-halogen flame-retardant composition is used. The composition constituting the insulating layer 10 or the sheath 20 and the composition constituting the surface protective layer 4 may be of the same type or different types. It is preferable to use the same kind of materials.

  By providing the surface protective layer 4 in this way, it is possible to improve the external appearance of the flame retardant electric wire and the flame retardant cable, and to further improve mechanical properties such as tensile strength and elongation. That is, the flame-retardant insulating layer 2 and the flame-retardant sheath 3 made of heat-expandable graphite or a non-halogen composition containing heat-expandable graphite and a red phosphorus flame retardant exhibit a lame-containing black to black dark color. Although the appearance is poor, by providing the surface protective layer 4, such appearance defects can be eliminated. In addition, by providing a layer that does not contain heat-expandable graphite or heat-expandable graphite and red phosphorus flame retardant, it is possible to provide heat-expandable graphite or flame retardant that contains heat-expandable graphite and red phosphorus flame retardant. The deterioration of the mechanical characteristics due to the provision of the insulating layer 2 or the flame retardant sheath 3 can be suppressed.

  The surface protective layer 4 preferably has a tensile strength of 10 MPa or more and an elongation of 350%, and a thickness of about 0.1 to 0.5 mm. If the thickness of the surface protective layer 4 is less than 0.1 mm, the effect of improving the appearance and mechanical properties is small, and if it exceeds 0.5 mm, flame retardancy and self-extinguishing properties are reduced.

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

Examples 1-4, Comparative Examples 1-4
Ethylene / vinyl acetate copolymer (trade name EVAFLEX EY180, manufactured by Mitsui DuPont Polychemical Co., Ltd.), expandable graphite (trade name, frame cut GREP-EG manufactured by Tosoh Corporation; 180 times expandability at 1000 ° C.), red phosphorus (phosphorus) Using a product name NOVARED 120) and magnesium hydroxide (trade name Kisuma 5A manufactured by Kyowa Chemical Industry Co., Ltd.) manufactured by Chemical Industry Co., Ltd., the components shown in Table 1 were uniformly kneaded to obtain a flame retardant resin composition. It was.

  Next, the obtained flame-retardant resin composition was subjected to 0.8 mm thick polyethylene insulation on a 1.8 mmφ annealed copper stranded conductor (7 pieces / 0.6 mmφ) using a general-purpose electric wire manufacturing extruder. A sheath having a thickness of 1.5 mm was formed by extrusion coating on an insulating wire core provided with a layer to produce a flame-retardant cable having an outer diameter of 6 and 4 mm.

The flame retardant resin composition obtained in each of the above Examples and Comparative Examples was 180 ° C. in a press machine.
A test sheet was produced by heating and pressing under a pressure of 20 MPa for 5 minutes, and the tensile strength and elongation were measured in accordance with JIS C 3005. Moreover, the oxygen index was measured based on JIS K7201. Further, a test sheet (6.5 mm × 150 mm × 1 mm) produced in the same manner was subjected to a vertical combustion test, and the combustion state after ignition (tyryl burner (flame height 19 mm) for 5 seconds indirect flame) was evaluated. These results are shown in the lower column of Table 1.

  As is clear from Table 1, the sheaths in the examples had self-extinguishing properties and good mechanical properties (tensile strength and elongation). On the other hand, none of the comparative examples had both self-extinguishing properties and good mechanical properties.

It is sectional drawing which shows one Embodiment of the flame-retardant electric wire of this invention. It is sectional drawing which shows one Embodiment of the flame-retardant cable of this invention. It is sectional drawing which shows other embodiment of the flame-retardant electric wire of this invention. It is sectional drawing which shows other embodiment of the flame-retardant cable of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Conductor, 2 ... Flame retardant insulation layer, 3 ... Flame retardant sheath, 4 ... Surface protective layer, 10, 30 ... Flame retardant electric wire, 20, 40 ... Flame retardant cable

Claims (8)

A flame retardant electric wire / cable with a non-halogen flame retardant coating mainly composed of an ethylene-based polymer on the outer periphery of the conductor,
The non-halogen flame retardant coating has a flame retardant layer comprising a non-halogen flame retardant composition containing 3 to 30 parts by weight of heat-expandable graphite with respect to 100 parts by weight of an ethylene polymer. ·cable.   The non-halogen flame retardant coating is composed of a non-halogen flame retardant composition containing 3 to 30 parts by weight of a red phosphorus flame retardant together with 3 to 30 parts by weight of heat-expandable graphite with respect to 100 parts by weight of an ethylene polymer. The flame-retardant wire / cable according to claim 1, further comprising a flame layer.   The ethylene polymer is at least one selected from the group consisting of polyethylene, polypropylene, ethylene / ethyl acrylate copolymer, ethylene / vinyl acetate copolymer, and ethylene / propylene copolymer. The flame-retardant electric wire / cable according to 1 or 2.   The flame-retardant electric wire / cable according to claim 3, wherein the ethylene polymer contains an ethylene / vinyl acetate copolymer.   5. The non-halogen flame retardant coating includes the flame retardant layer and a surface protective layer substantially not containing heat-expandable graphite provided on an outer periphery thereof. Flame retardant wire / cable as described in section   The flame retardant wire / cable according to claim 5, wherein the surface protective layer has a tensile strength of 10 MPa or more and an elongation of 350%.   3. The non-halogen flame retardant coating has the flame retardant layer and a surface protective layer substantially free of heat-expandable graphite and red phosphorus flame retardant provided on the outer periphery thereof. The flame-retardant electric wire / cable of any one of thru | or 4.   The flame retardant wire / cable according to claim 7, wherein the surface protective layer has a tensile strength of 10 MPa or more and an elongation of 350%.

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